4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
19 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
30 #include <linux/module.h>
31 #include <linux/nmi.h>
32 #include <linux/init.h>
33 #include <linux/uaccess.h>
34 #include <linux/highmem.h>
35 #include <linux/smp_lock.h>
36 #include <asm/mmu_context.h>
37 #include <linux/interrupt.h>
38 #include <linux/capability.h>
39 #include <linux/completion.h>
40 #include <linux/kernel_stat.h>
41 #include <linux/debug_locks.h>
42 #include <linux/security.h>
43 #include <linux/notifier.h>
44 #include <linux/profile.h>
45 #include <linux/freezer.h>
46 #include <linux/vmalloc.h>
47 #include <linux/blkdev.h>
48 #include <linux/delay.h>
49 #include <linux/pid_namespace.h>
50 #include <linux/smp.h>
51 #include <linux/threads.h>
52 #include <linux/timer.h>
53 #include <linux/rcupdate.h>
54 #include <linux/cpu.h>
55 #include <linux/cpuset.h>
56 #include <linux/percpu.h>
57 #include <linux/kthread.h>
58 #include <linux/seq_file.h>
59 #include <linux/sysctl.h>
60 #include <linux/syscalls.h>
61 #include <linux/times.h>
62 #include <linux/tsacct_kern.h>
63 #include <linux/kprobes.h>
64 #include <linux/delayacct.h>
65 #include <linux/reciprocal_div.h>
66 #include <linux/unistd.h>
67 #include <linux/pagemap.h>
68 #include <linux/hrtimer.h>
69 #include <linux/tick.h>
70 #include <linux/bootmem.h>
71 #include <linux/debugfs.h>
72 #include <linux/ctype.h>
73 #include <linux/ftrace.h>
76 #include <asm/irq_regs.h>
79 * Convert user-nice values [ -20 ... 0 ... 19 ]
80 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
83 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
84 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
85 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
88 * 'User priority' is the nice value converted to something we
89 * can work with better when scaling various scheduler parameters,
90 * it's a [ 0 ... 39 ] range.
92 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
93 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
94 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
97 * Helpers for converting nanosecond timing to jiffy resolution
99 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
101 #define NICE_0_LOAD SCHED_LOAD_SCALE
102 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
105 * These are the 'tuning knobs' of the scheduler:
107 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
108 * Timeslices get refilled after they expire.
110 #define DEF_TIMESLICE (100 * HZ / 1000)
113 * single value that denotes runtime == period, ie unlimited time.
115 #define RUNTIME_INF ((u64)~0ULL)
119 * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
120 * Since cpu_power is a 'constant', we can use a reciprocal divide.
122 static inline u32
sg_div_cpu_power(const struct sched_group
*sg
, u32 load
)
124 return reciprocal_divide(load
, sg
->reciprocal_cpu_power
);
128 * Each time a sched group cpu_power is changed,
129 * we must compute its reciprocal value
131 static inline void sg_inc_cpu_power(struct sched_group
*sg
, u32 val
)
133 sg
->__cpu_power
+= val
;
134 sg
->reciprocal_cpu_power
= reciprocal_value(sg
->__cpu_power
);
138 static inline int rt_policy(int policy
)
140 if (unlikely(policy
== SCHED_FIFO
|| policy
== SCHED_RR
))
145 static inline int task_has_rt_policy(struct task_struct
*p
)
147 return rt_policy(p
->policy
);
151 * This is the priority-queue data structure of the RT scheduling class:
153 struct rt_prio_array
{
154 DECLARE_BITMAP(bitmap
, MAX_RT_PRIO
+1); /* include 1 bit for delimiter */
155 struct list_head queue
[MAX_RT_PRIO
];
158 struct rt_bandwidth
{
159 /* nests inside the rq lock: */
160 spinlock_t rt_runtime_lock
;
163 struct hrtimer rt_period_timer
;
166 static struct rt_bandwidth def_rt_bandwidth
;
168 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
170 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
172 struct rt_bandwidth
*rt_b
=
173 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
179 now
= hrtimer_cb_get_time(timer
);
180 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
185 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
188 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
192 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
194 rt_b
->rt_period
= ns_to_ktime(period
);
195 rt_b
->rt_runtime
= runtime
;
197 spin_lock_init(&rt_b
->rt_runtime_lock
);
199 hrtimer_init(&rt_b
->rt_period_timer
,
200 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
201 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
202 rt_b
->rt_period_timer
.cb_mode
= HRTIMER_CB_IRQSAFE_NO_SOFTIRQ
;
205 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
209 if (rt_b
->rt_runtime
== RUNTIME_INF
)
212 if (hrtimer_active(&rt_b
->rt_period_timer
))
215 spin_lock(&rt_b
->rt_runtime_lock
);
217 if (hrtimer_active(&rt_b
->rt_period_timer
))
220 now
= hrtimer_cb_get_time(&rt_b
->rt_period_timer
);
221 hrtimer_forward(&rt_b
->rt_period_timer
, now
, rt_b
->rt_period
);
222 hrtimer_start(&rt_b
->rt_period_timer
,
223 rt_b
->rt_period_timer
.expires
,
226 spin_unlock(&rt_b
->rt_runtime_lock
);
229 #ifdef CONFIG_RT_GROUP_SCHED
230 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
232 hrtimer_cancel(&rt_b
->rt_period_timer
);
237 * sched_domains_mutex serializes calls to arch_init_sched_domains,
238 * detach_destroy_domains and partition_sched_domains.
240 static DEFINE_MUTEX(sched_domains_mutex
);
242 #ifdef CONFIG_GROUP_SCHED
244 #include <linux/cgroup.h>
248 static LIST_HEAD(task_groups
);
250 /* task group related information */
252 #ifdef CONFIG_CGROUP_SCHED
253 struct cgroup_subsys_state css
;
256 #ifdef CONFIG_FAIR_GROUP_SCHED
257 /* schedulable entities of this group on each cpu */
258 struct sched_entity
**se
;
259 /* runqueue "owned" by this group on each cpu */
260 struct cfs_rq
**cfs_rq
;
261 unsigned long shares
;
264 #ifdef CONFIG_RT_GROUP_SCHED
265 struct sched_rt_entity
**rt_se
;
266 struct rt_rq
**rt_rq
;
268 struct rt_bandwidth rt_bandwidth
;
272 struct list_head list
;
274 struct task_group
*parent
;
275 struct list_head siblings
;
276 struct list_head children
;
279 #ifdef CONFIG_USER_SCHED
283 * Every UID task group (including init_task_group aka UID-0) will
284 * be a child to this group.
286 struct task_group root_task_group
;
288 #ifdef CONFIG_FAIR_GROUP_SCHED
289 /* Default task group's sched entity on each cpu */
290 static DEFINE_PER_CPU(struct sched_entity
, init_sched_entity
);
291 /* Default task group's cfs_rq on each cpu */
292 static DEFINE_PER_CPU(struct cfs_rq
, init_cfs_rq
) ____cacheline_aligned_in_smp
;
295 #ifdef CONFIG_RT_GROUP_SCHED
296 static DEFINE_PER_CPU(struct sched_rt_entity
, init_sched_rt_entity
);
297 static DEFINE_PER_CPU(struct rt_rq
, init_rt_rq
) ____cacheline_aligned_in_smp
;
300 #define root_task_group init_task_group
303 /* task_group_lock serializes add/remove of task groups and also changes to
304 * a task group's cpu shares.
306 static DEFINE_SPINLOCK(task_group_lock
);
308 #ifdef CONFIG_FAIR_GROUP_SCHED
309 #ifdef CONFIG_USER_SCHED
310 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
312 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
316 * A weight of 0 or 1 can cause arithmetics problems.
317 * A weight of a cfs_rq is the sum of weights of which entities
318 * are queued on this cfs_rq, so a weight of a entity should not be
319 * too large, so as the shares value of a task group.
320 * (The default weight is 1024 - so there's no practical
321 * limitation from this.)
324 #define MAX_SHARES (1UL << 18)
326 static int init_task_group_load
= INIT_TASK_GROUP_LOAD
;
329 /* Default task group.
330 * Every task in system belong to this group at bootup.
332 struct task_group init_task_group
;
334 /* return group to which a task belongs */
335 static inline struct task_group
*task_group(struct task_struct
*p
)
337 struct task_group
*tg
;
339 #ifdef CONFIG_USER_SCHED
341 #elif defined(CONFIG_CGROUP_SCHED)
342 tg
= container_of(task_subsys_state(p
, cpu_cgroup_subsys_id
),
343 struct task_group
, css
);
345 tg
= &init_task_group
;
350 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
351 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
353 #ifdef CONFIG_FAIR_GROUP_SCHED
354 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
355 p
->se
.parent
= task_group(p
)->se
[cpu
];
358 #ifdef CONFIG_RT_GROUP_SCHED
359 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
360 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
366 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
368 #endif /* CONFIG_GROUP_SCHED */
370 /* CFS-related fields in a runqueue */
372 struct load_weight load
;
373 unsigned long nr_running
;
378 struct rb_root tasks_timeline
;
379 struct rb_node
*rb_leftmost
;
381 struct list_head tasks
;
382 struct list_head
*balance_iterator
;
385 * 'curr' points to currently running entity on this cfs_rq.
386 * It is set to NULL otherwise (i.e when none are currently running).
388 struct sched_entity
*curr
, *next
;
390 unsigned long nr_spread_over
;
392 #ifdef CONFIG_FAIR_GROUP_SCHED
393 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
396 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
397 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
398 * (like users, containers etc.)
400 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
401 * list is used during load balance.
403 struct list_head leaf_cfs_rq_list
;
404 struct task_group
*tg
; /* group that "owns" this runqueue */
408 /* Real-Time classes' related field in a runqueue: */
410 struct rt_prio_array active
;
411 unsigned long rt_nr_running
;
412 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
413 int highest_prio
; /* highest queued rt task prio */
416 unsigned long rt_nr_migratory
;
422 /* Nests inside the rq lock: */
423 spinlock_t rt_runtime_lock
;
425 #ifdef CONFIG_RT_GROUP_SCHED
426 unsigned long rt_nr_boosted
;
429 struct list_head leaf_rt_rq_list
;
430 struct task_group
*tg
;
431 struct sched_rt_entity
*rt_se
;
438 * We add the notion of a root-domain which will be used to define per-domain
439 * variables. Each exclusive cpuset essentially defines an island domain by
440 * fully partitioning the member cpus from any other cpuset. Whenever a new
441 * exclusive cpuset is created, we also create and attach a new root-domain
451 * The "RT overload" flag: it gets set if a CPU has more than
452 * one runnable RT task.
459 * By default the system creates a single root-domain with all cpus as
460 * members (mimicking the global state we have today).
462 static struct root_domain def_root_domain
;
467 * This is the main, per-CPU runqueue data structure.
469 * Locking rule: those places that want to lock multiple runqueues
470 * (such as the load balancing or the thread migration code), lock
471 * acquire operations must be ordered by ascending &runqueue.
478 * nr_running and cpu_load should be in the same cacheline because
479 * remote CPUs use both these fields when doing load calculation.
481 unsigned long nr_running
;
482 #define CPU_LOAD_IDX_MAX 5
483 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
484 unsigned char idle_at_tick
;
486 unsigned long last_tick_seen
;
487 unsigned char in_nohz_recently
;
489 /* capture load from *all* tasks on this cpu: */
490 struct load_weight load
;
491 unsigned long nr_load_updates
;
497 #ifdef CONFIG_FAIR_GROUP_SCHED
498 /* list of leaf cfs_rq on this cpu: */
499 struct list_head leaf_cfs_rq_list
;
501 #ifdef CONFIG_RT_GROUP_SCHED
502 struct list_head leaf_rt_rq_list
;
506 * This is part of a global counter where only the total sum
507 * over all CPUs matters. A task can increase this counter on
508 * one CPU and if it got migrated afterwards it may decrease
509 * it on another CPU. Always updated under the runqueue lock:
511 unsigned long nr_uninterruptible
;
513 struct task_struct
*curr
, *idle
;
514 unsigned long next_balance
;
515 struct mm_struct
*prev_mm
;
522 struct root_domain
*rd
;
523 struct sched_domain
*sd
;
525 /* For active balancing */
528 /* cpu of this runqueue: */
531 struct task_struct
*migration_thread
;
532 struct list_head migration_queue
;
535 #ifdef CONFIG_SCHED_HRTICK
536 unsigned long hrtick_flags
;
537 ktime_t hrtick_expire
;
538 struct hrtimer hrtick_timer
;
541 #ifdef CONFIG_SCHEDSTATS
543 struct sched_info rq_sched_info
;
545 /* sys_sched_yield() stats */
546 unsigned int yld_exp_empty
;
547 unsigned int yld_act_empty
;
548 unsigned int yld_both_empty
;
549 unsigned int yld_count
;
551 /* schedule() stats */
552 unsigned int sched_switch
;
553 unsigned int sched_count
;
554 unsigned int sched_goidle
;
556 /* try_to_wake_up() stats */
557 unsigned int ttwu_count
;
558 unsigned int ttwu_local
;
561 unsigned int bkl_count
;
563 struct lock_class_key rq_lock_key
;
566 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
568 static inline void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
)
570 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
);
573 static inline int cpu_of(struct rq
*rq
)
583 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
584 * See detach_destroy_domains: synchronize_sched for details.
586 * The domain tree of any CPU may only be accessed from within
587 * preempt-disabled sections.
589 #define for_each_domain(cpu, __sd) \
590 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
592 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
593 #define this_rq() (&__get_cpu_var(runqueues))
594 #define task_rq(p) cpu_rq(task_cpu(p))
595 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
597 static inline void update_rq_clock(struct rq
*rq
)
599 rq
->clock
= sched_clock_cpu(cpu_of(rq
));
603 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
605 #ifdef CONFIG_SCHED_DEBUG
606 # define const_debug __read_mostly
608 # define const_debug static const
614 * Returns true if the current cpu runqueue is locked.
615 * This interface allows printk to be called with the runqueue lock
616 * held and know whether or not it is OK to wake up the klogd.
618 int runqueue_is_locked(void)
621 struct rq
*rq
= cpu_rq(cpu
);
624 ret
= spin_is_locked(&rq
->lock
);
630 * Debugging: various feature bits
633 #define SCHED_FEAT(name, enabled) \
634 __SCHED_FEAT_##name ,
637 #include "sched_features.h"
642 #define SCHED_FEAT(name, enabled) \
643 (1UL << __SCHED_FEAT_##name) * enabled |
645 const_debug
unsigned int sysctl_sched_features
=
646 #include "sched_features.h"
651 #ifdef CONFIG_SCHED_DEBUG
652 #define SCHED_FEAT(name, enabled) \
655 static __read_mostly
char *sched_feat_names
[] = {
656 #include "sched_features.h"
662 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
664 filp
->private_data
= inode
->i_private
;
669 sched_feat_read(struct file
*filp
, char __user
*ubuf
,
670 size_t cnt
, loff_t
*ppos
)
677 for (i
= 0; sched_feat_names
[i
]; i
++) {
678 len
+= strlen(sched_feat_names
[i
]);
682 buf
= kmalloc(len
+ 2, GFP_KERNEL
);
686 for (i
= 0; sched_feat_names
[i
]; i
++) {
687 if (sysctl_sched_features
& (1UL << i
))
688 r
+= sprintf(buf
+ r
, "%s ", sched_feat_names
[i
]);
690 r
+= sprintf(buf
+ r
, "NO_%s ", sched_feat_names
[i
]);
693 r
+= sprintf(buf
+ r
, "\n");
694 WARN_ON(r
>= len
+ 2);
696 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
704 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
705 size_t cnt
, loff_t
*ppos
)
715 if (copy_from_user(&buf
, ubuf
, cnt
))
720 if (strncmp(buf
, "NO_", 3) == 0) {
725 for (i
= 0; sched_feat_names
[i
]; i
++) {
726 int len
= strlen(sched_feat_names
[i
]);
728 if (strncmp(cmp
, sched_feat_names
[i
], len
) == 0) {
730 sysctl_sched_features
&= ~(1UL << i
);
732 sysctl_sched_features
|= (1UL << i
);
737 if (!sched_feat_names
[i
])
745 static struct file_operations sched_feat_fops
= {
746 .open
= sched_feat_open
,
747 .read
= sched_feat_read
,
748 .write
= sched_feat_write
,
751 static __init
int sched_init_debug(void)
753 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
758 late_initcall(sched_init_debug
);
762 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
765 * Number of tasks to iterate in a single balance run.
766 * Limited because this is done with IRQs disabled.
768 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
771 * period over which we measure -rt task cpu usage in us.
774 unsigned int sysctl_sched_rt_period
= 1000000;
776 static __read_mostly
int scheduler_running
;
779 * part of the period that we allow rt tasks to run in us.
782 int sysctl_sched_rt_runtime
= 950000;
784 static inline u64
global_rt_period(void)
786 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
789 static inline u64
global_rt_runtime(void)
791 if (sysctl_sched_rt_period
< 0)
794 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
797 unsigned long long time_sync_thresh
= 100000;
799 static DEFINE_PER_CPU(unsigned long long, time_offset
);
800 static DEFINE_PER_CPU(unsigned long long, prev_cpu_time
);
803 * Global lock which we take every now and then to synchronize
804 * the CPUs time. This method is not warp-safe, but it's good
805 * enough to synchronize slowly diverging time sources and thus
806 * it's good enough for tracing:
808 static DEFINE_SPINLOCK(time_sync_lock
);
809 static unsigned long long prev_global_time
;
811 static unsigned long long __sync_cpu_clock(unsigned long long time
, int cpu
)
814 * We want this inlined, to not get tracer function calls
815 * in this critical section:
817 spin_acquire(&time_sync_lock
.dep_map
, 0, 0, _THIS_IP_
);
818 __raw_spin_lock(&time_sync_lock
.raw_lock
);
820 if (time
< prev_global_time
) {
821 per_cpu(time_offset
, cpu
) += prev_global_time
- time
;
822 time
= prev_global_time
;
824 prev_global_time
= time
;
827 __raw_spin_unlock(&time_sync_lock
.raw_lock
);
828 spin_release(&time_sync_lock
.dep_map
, 1, _THIS_IP_
);
833 static unsigned long long __cpu_clock(int cpu
)
835 unsigned long long now
;
838 * Only call sched_clock() if the scheduler has already been
839 * initialized (some code might call cpu_clock() very early):
841 if (unlikely(!scheduler_running
))
844 now
= sched_clock_cpu(cpu
);
850 * For kernel-internal use: high-speed (but slightly incorrect) per-cpu
851 * clock constructed from sched_clock():
853 unsigned long long notrace
cpu_clock(int cpu
)
855 unsigned long long prev_cpu_time
, time
, delta_time
;
858 local_irq_save(flags
);
859 prev_cpu_time
= per_cpu(prev_cpu_time
, cpu
);
860 time
= __cpu_clock(cpu
) + per_cpu(time_offset
, cpu
);
861 delta_time
= time
-prev_cpu_time
;
863 if (unlikely(delta_time
> time_sync_thresh
)) {
864 time
= __sync_cpu_clock(time
, cpu
);
865 per_cpu(prev_cpu_time
, cpu
) = time
;
867 local_irq_restore(flags
);
871 EXPORT_SYMBOL_GPL(cpu_clock
);
873 #ifndef prepare_arch_switch
874 # define prepare_arch_switch(next) do { } while (0)
876 #ifndef finish_arch_switch
877 # define finish_arch_switch(prev) do { } while (0)
880 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
882 return rq
->curr
== p
;
885 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
886 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
888 return task_current(rq
, p
);
891 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
895 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
897 #ifdef CONFIG_DEBUG_SPINLOCK
898 /* this is a valid case when another task releases the spinlock */
899 rq
->lock
.owner
= current
;
902 * If we are tracking spinlock dependencies then we have to
903 * fix up the runqueue lock - which gets 'carried over' from
906 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
908 spin_unlock_irq(&rq
->lock
);
911 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
912 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
917 return task_current(rq
, p
);
921 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
925 * We can optimise this out completely for !SMP, because the
926 * SMP rebalancing from interrupt is the only thing that cares
931 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
932 spin_unlock_irq(&rq
->lock
);
934 spin_unlock(&rq
->lock
);
938 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
942 * After ->oncpu is cleared, the task can be moved to a different CPU.
943 * We must ensure this doesn't happen until the switch is completely
949 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
953 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
956 * __task_rq_lock - lock the runqueue a given task resides on.
957 * Must be called interrupts disabled.
959 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
963 struct rq
*rq
= task_rq(p
);
964 spin_lock(&rq
->lock
);
965 if (likely(rq
== task_rq(p
)))
967 spin_unlock(&rq
->lock
);
972 * task_rq_lock - lock the runqueue a given task resides on and disable
973 * interrupts. Note the ordering: we can safely lookup the task_rq without
974 * explicitly disabling preemption.
976 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
982 local_irq_save(*flags
);
984 spin_lock(&rq
->lock
);
985 if (likely(rq
== task_rq(p
)))
987 spin_unlock_irqrestore(&rq
->lock
, *flags
);
991 static void __task_rq_unlock(struct rq
*rq
)
994 spin_unlock(&rq
->lock
);
997 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
1000 spin_unlock_irqrestore(&rq
->lock
, *flags
);
1004 * this_rq_lock - lock this runqueue and disable interrupts.
1006 static struct rq
*this_rq_lock(void)
1007 __acquires(rq
->lock
)
1011 local_irq_disable();
1013 spin_lock(&rq
->lock
);
1018 static void __resched_task(struct task_struct
*p
, int tif_bit
);
1020 static inline void resched_task(struct task_struct
*p
)
1022 __resched_task(p
, TIF_NEED_RESCHED
);
1025 #ifdef CONFIG_SCHED_HRTICK
1027 * Use HR-timers to deliver accurate preemption points.
1029 * Its all a bit involved since we cannot program an hrt while holding the
1030 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1033 * When we get rescheduled we reprogram the hrtick_timer outside of the
1036 static inline void resched_hrt(struct task_struct
*p
)
1038 __resched_task(p
, TIF_HRTICK_RESCHED
);
1041 static inline void resched_rq(struct rq
*rq
)
1043 unsigned long flags
;
1045 spin_lock_irqsave(&rq
->lock
, flags
);
1046 resched_task(rq
->curr
);
1047 spin_unlock_irqrestore(&rq
->lock
, flags
);
1051 HRTICK_SET
, /* re-programm hrtick_timer */
1052 HRTICK_RESET
, /* not a new slice */
1053 HRTICK_BLOCK
, /* stop hrtick operations */
1058 * - enabled by features
1059 * - hrtimer is actually high res
1061 static inline int hrtick_enabled(struct rq
*rq
)
1063 if (!sched_feat(HRTICK
))
1065 if (unlikely(test_bit(HRTICK_BLOCK
, &rq
->hrtick_flags
)))
1067 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1071 * Called to set the hrtick timer state.
1073 * called with rq->lock held and irqs disabled
1075 static void hrtick_start(struct rq
*rq
, u64 delay
, int reset
)
1077 assert_spin_locked(&rq
->lock
);
1080 * preempt at: now + delay
1083 ktime_add_ns(rq
->hrtick_timer
.base
->get_time(), delay
);
1085 * indicate we need to program the timer
1087 __set_bit(HRTICK_SET
, &rq
->hrtick_flags
);
1089 __set_bit(HRTICK_RESET
, &rq
->hrtick_flags
);
1092 * New slices are called from the schedule path and don't need a
1093 * forced reschedule.
1096 resched_hrt(rq
->curr
);
1099 static void hrtick_clear(struct rq
*rq
)
1101 if (hrtimer_active(&rq
->hrtick_timer
))
1102 hrtimer_cancel(&rq
->hrtick_timer
);
1106 * Update the timer from the possible pending state.
1108 static void hrtick_set(struct rq
*rq
)
1112 unsigned long flags
;
1114 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1116 spin_lock_irqsave(&rq
->lock
, flags
);
1117 set
= __test_and_clear_bit(HRTICK_SET
, &rq
->hrtick_flags
);
1118 reset
= __test_and_clear_bit(HRTICK_RESET
, &rq
->hrtick_flags
);
1119 time
= rq
->hrtick_expire
;
1120 clear_thread_flag(TIF_HRTICK_RESCHED
);
1121 spin_unlock_irqrestore(&rq
->lock
, flags
);
1124 hrtimer_start(&rq
->hrtick_timer
, time
, HRTIMER_MODE_ABS
);
1125 if (reset
&& !hrtimer_active(&rq
->hrtick_timer
))
1132 * High-resolution timer tick.
1133 * Runs from hardirq context with interrupts disabled.
1135 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1137 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1139 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1141 spin_lock(&rq
->lock
);
1142 update_rq_clock(rq
);
1143 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1144 spin_unlock(&rq
->lock
);
1146 return HRTIMER_NORESTART
;
1149 static void hotplug_hrtick_disable(int cpu
)
1151 struct rq
*rq
= cpu_rq(cpu
);
1152 unsigned long flags
;
1154 spin_lock_irqsave(&rq
->lock
, flags
);
1155 rq
->hrtick_flags
= 0;
1156 __set_bit(HRTICK_BLOCK
, &rq
->hrtick_flags
);
1157 spin_unlock_irqrestore(&rq
->lock
, flags
);
1162 static void hotplug_hrtick_enable(int cpu
)
1164 struct rq
*rq
= cpu_rq(cpu
);
1165 unsigned long flags
;
1167 spin_lock_irqsave(&rq
->lock
, flags
);
1168 __clear_bit(HRTICK_BLOCK
, &rq
->hrtick_flags
);
1169 spin_unlock_irqrestore(&rq
->lock
, flags
);
1173 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
1175 int cpu
= (int)(long)hcpu
;
1178 case CPU_UP_CANCELED
:
1179 case CPU_UP_CANCELED_FROZEN
:
1180 case CPU_DOWN_PREPARE
:
1181 case CPU_DOWN_PREPARE_FROZEN
:
1183 case CPU_DEAD_FROZEN
:
1184 hotplug_hrtick_disable(cpu
);
1187 case CPU_UP_PREPARE
:
1188 case CPU_UP_PREPARE_FROZEN
:
1189 case CPU_DOWN_FAILED
:
1190 case CPU_DOWN_FAILED_FROZEN
:
1192 case CPU_ONLINE_FROZEN
:
1193 hotplug_hrtick_enable(cpu
);
1200 static void init_hrtick(void)
1202 hotcpu_notifier(hotplug_hrtick
, 0);
1205 static void init_rq_hrtick(struct rq
*rq
)
1207 rq
->hrtick_flags
= 0;
1208 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1209 rq
->hrtick_timer
.function
= hrtick
;
1210 rq
->hrtick_timer
.cb_mode
= HRTIMER_CB_IRQSAFE_NO_SOFTIRQ
;
1213 void hrtick_resched(void)
1216 unsigned long flags
;
1218 if (!test_thread_flag(TIF_HRTICK_RESCHED
))
1221 local_irq_save(flags
);
1222 rq
= cpu_rq(smp_processor_id());
1224 local_irq_restore(flags
);
1227 static inline void hrtick_clear(struct rq
*rq
)
1231 static inline void hrtick_set(struct rq
*rq
)
1235 static inline void init_rq_hrtick(struct rq
*rq
)
1239 void hrtick_resched(void)
1243 static inline void init_hrtick(void)
1249 * resched_task - mark a task 'to be rescheduled now'.
1251 * On UP this means the setting of the need_resched flag, on SMP it
1252 * might also involve a cross-CPU call to trigger the scheduler on
1257 #ifndef tsk_is_polling
1258 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1261 static void __resched_task(struct task_struct
*p
, int tif_bit
)
1265 assert_spin_locked(&task_rq(p
)->lock
);
1267 if (unlikely(test_tsk_thread_flag(p
, tif_bit
)))
1270 set_tsk_thread_flag(p
, tif_bit
);
1273 if (cpu
== smp_processor_id())
1276 /* NEED_RESCHED must be visible before we test polling */
1278 if (!tsk_is_polling(p
))
1279 smp_send_reschedule(cpu
);
1282 static void resched_cpu(int cpu
)
1284 struct rq
*rq
= cpu_rq(cpu
);
1285 unsigned long flags
;
1287 if (!spin_trylock_irqsave(&rq
->lock
, flags
))
1289 resched_task(cpu_curr(cpu
));
1290 spin_unlock_irqrestore(&rq
->lock
, flags
);
1295 * When add_timer_on() enqueues a timer into the timer wheel of an
1296 * idle CPU then this timer might expire before the next timer event
1297 * which is scheduled to wake up that CPU. In case of a completely
1298 * idle system the next event might even be infinite time into the
1299 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1300 * leaves the inner idle loop so the newly added timer is taken into
1301 * account when the CPU goes back to idle and evaluates the timer
1302 * wheel for the next timer event.
1304 void wake_up_idle_cpu(int cpu
)
1306 struct rq
*rq
= cpu_rq(cpu
);
1308 if (cpu
== smp_processor_id())
1312 * This is safe, as this function is called with the timer
1313 * wheel base lock of (cpu) held. When the CPU is on the way
1314 * to idle and has not yet set rq->curr to idle then it will
1315 * be serialized on the timer wheel base lock and take the new
1316 * timer into account automatically.
1318 if (rq
->curr
!= rq
->idle
)
1322 * We can set TIF_RESCHED on the idle task of the other CPU
1323 * lockless. The worst case is that the other CPU runs the
1324 * idle task through an additional NOOP schedule()
1326 set_tsk_thread_flag(rq
->idle
, TIF_NEED_RESCHED
);
1328 /* NEED_RESCHED must be visible before we test polling */
1330 if (!tsk_is_polling(rq
->idle
))
1331 smp_send_reschedule(cpu
);
1336 static void __resched_task(struct task_struct
*p
, int tif_bit
)
1338 assert_spin_locked(&task_rq(p
)->lock
);
1339 set_tsk_thread_flag(p
, tif_bit
);
1343 #if BITS_PER_LONG == 32
1344 # define WMULT_CONST (~0UL)
1346 # define WMULT_CONST (1UL << 32)
1349 #define WMULT_SHIFT 32
1352 * Shift right and round:
1354 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1356 static unsigned long
1357 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1358 struct load_weight
*lw
)
1362 if (!lw
->inv_weight
) {
1363 if (BITS_PER_LONG
> 32 && unlikely(lw
->weight
>= WMULT_CONST
))
1366 lw
->inv_weight
= 1 + (WMULT_CONST
-lw
->weight
/2)
1370 tmp
= (u64
)delta_exec
* weight
;
1372 * Check whether we'd overflow the 64-bit multiplication:
1374 if (unlikely(tmp
> WMULT_CONST
))
1375 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1378 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1380 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1383 static inline unsigned long
1384 calc_delta_fair(unsigned long delta_exec
, struct load_weight
*lw
)
1386 return calc_delta_mine(delta_exec
, NICE_0_LOAD
, lw
);
1389 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1395 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1402 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1403 * of tasks with abnormal "nice" values across CPUs the contribution that
1404 * each task makes to its run queue's load is weighted according to its
1405 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1406 * scaled version of the new time slice allocation that they receive on time
1410 #define WEIGHT_IDLEPRIO 2
1411 #define WMULT_IDLEPRIO (1 << 31)
1414 * Nice levels are multiplicative, with a gentle 10% change for every
1415 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1416 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1417 * that remained on nice 0.
1419 * The "10% effect" is relative and cumulative: from _any_ nice level,
1420 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1421 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1422 * If a task goes up by ~10% and another task goes down by ~10% then
1423 * the relative distance between them is ~25%.)
1425 static const int prio_to_weight
[40] = {
1426 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1427 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1428 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1429 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1430 /* 0 */ 1024, 820, 655, 526, 423,
1431 /* 5 */ 335, 272, 215, 172, 137,
1432 /* 10 */ 110, 87, 70, 56, 45,
1433 /* 15 */ 36, 29, 23, 18, 15,
1437 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1439 * In cases where the weight does not change often, we can use the
1440 * precalculated inverse to speed up arithmetics by turning divisions
1441 * into multiplications:
1443 static const u32 prio_to_wmult
[40] = {
1444 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1445 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1446 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1447 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1448 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1449 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1450 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1451 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1454 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
);
1457 * runqueue iterator, to support SMP load-balancing between different
1458 * scheduling classes, without having to expose their internal data
1459 * structures to the load-balancing proper:
1461 struct rq_iterator
{
1463 struct task_struct
*(*start
)(void *);
1464 struct task_struct
*(*next
)(void *);
1468 static unsigned long
1469 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1470 unsigned long max_load_move
, struct sched_domain
*sd
,
1471 enum cpu_idle_type idle
, int *all_pinned
,
1472 int *this_best_prio
, struct rq_iterator
*iterator
);
1475 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1476 struct sched_domain
*sd
, enum cpu_idle_type idle
,
1477 struct rq_iterator
*iterator
);
1480 #ifdef CONFIG_CGROUP_CPUACCT
1481 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1483 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1486 static inline void inc_cpu_load(struct rq
*rq
, unsigned long load
)
1488 update_load_add(&rq
->load
, load
);
1491 static inline void dec_cpu_load(struct rq
*rq
, unsigned long load
)
1493 update_load_sub(&rq
->load
, load
);
1497 static unsigned long source_load(int cpu
, int type
);
1498 static unsigned long target_load(int cpu
, int type
);
1499 static unsigned long cpu_avg_load_per_task(int cpu
);
1500 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1501 #else /* CONFIG_SMP */
1503 #ifdef CONFIG_FAIR_GROUP_SCHED
1504 static void cfs_rq_set_shares(struct cfs_rq
*cfs_rq
, unsigned long shares
)
1509 #endif /* CONFIG_SMP */
1511 #include "sched_stats.h"
1512 #include "sched_idletask.c"
1513 #include "sched_fair.c"
1514 #include "sched_rt.c"
1515 #ifdef CONFIG_SCHED_DEBUG
1516 # include "sched_debug.c"
1519 #define sched_class_highest (&rt_sched_class)
1521 static inline void inc_load(struct rq
*rq
, const struct task_struct
*p
)
1523 update_load_add(&rq
->load
, p
->se
.load
.weight
);
1526 static inline void dec_load(struct rq
*rq
, const struct task_struct
*p
)
1528 update_load_sub(&rq
->load
, p
->se
.load
.weight
);
1531 static void inc_nr_running(struct task_struct
*p
, struct rq
*rq
)
1537 static void dec_nr_running(struct task_struct
*p
, struct rq
*rq
)
1543 static void set_load_weight(struct task_struct
*p
)
1545 if (task_has_rt_policy(p
)) {
1546 p
->se
.load
.weight
= prio_to_weight
[0] * 2;
1547 p
->se
.load
.inv_weight
= prio_to_wmult
[0] >> 1;
1552 * SCHED_IDLE tasks get minimal weight:
1554 if (p
->policy
== SCHED_IDLE
) {
1555 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1556 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1560 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1561 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1564 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1566 sched_info_queued(p
);
1567 p
->sched_class
->enqueue_task(rq
, p
, wakeup
);
1571 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1573 p
->sched_class
->dequeue_task(rq
, p
, sleep
);
1578 * __normal_prio - return the priority that is based on the static prio
1580 static inline int __normal_prio(struct task_struct
*p
)
1582 return p
->static_prio
;
1586 * Calculate the expected normal priority: i.e. priority
1587 * without taking RT-inheritance into account. Might be
1588 * boosted by interactivity modifiers. Changes upon fork,
1589 * setprio syscalls, and whenever the interactivity
1590 * estimator recalculates.
1592 static inline int normal_prio(struct task_struct
*p
)
1596 if (task_has_rt_policy(p
))
1597 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1599 prio
= __normal_prio(p
);
1604 * Calculate the current priority, i.e. the priority
1605 * taken into account by the scheduler. This value might
1606 * be boosted by RT tasks, or might be boosted by
1607 * interactivity modifiers. Will be RT if the task got
1608 * RT-boosted. If not then it returns p->normal_prio.
1610 static int effective_prio(struct task_struct
*p
)
1612 p
->normal_prio
= normal_prio(p
);
1614 * If we are RT tasks or we were boosted to RT priority,
1615 * keep the priority unchanged. Otherwise, update priority
1616 * to the normal priority:
1618 if (!rt_prio(p
->prio
))
1619 return p
->normal_prio
;
1624 * activate_task - move a task to the runqueue.
1626 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1628 if (task_contributes_to_load(p
))
1629 rq
->nr_uninterruptible
--;
1631 enqueue_task(rq
, p
, wakeup
);
1632 inc_nr_running(p
, rq
);
1636 * deactivate_task - remove a task from the runqueue.
1638 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1640 if (task_contributes_to_load(p
))
1641 rq
->nr_uninterruptible
++;
1643 dequeue_task(rq
, p
, sleep
);
1644 dec_nr_running(p
, rq
);
1648 * task_curr - is this task currently executing on a CPU?
1649 * @p: the task in question.
1651 inline int task_curr(const struct task_struct
*p
)
1653 return cpu_curr(task_cpu(p
)) == p
;
1656 /* Used instead of source_load when we know the type == 0 */
1657 unsigned long weighted_cpuload(const int cpu
)
1659 return cpu_rq(cpu
)->load
.weight
;
1662 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1664 set_task_rq(p
, cpu
);
1667 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1668 * successfuly executed on another CPU. We must ensure that updates of
1669 * per-task data have been completed by this moment.
1672 task_thread_info(p
)->cpu
= cpu
;
1676 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1677 const struct sched_class
*prev_class
,
1678 int oldprio
, int running
)
1680 if (prev_class
!= p
->sched_class
) {
1681 if (prev_class
->switched_from
)
1682 prev_class
->switched_from(rq
, p
, running
);
1683 p
->sched_class
->switched_to(rq
, p
, running
);
1685 p
->sched_class
->prio_changed(rq
, p
, oldprio
, running
);
1691 * Is this task likely cache-hot:
1694 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
1699 * Buddy candidates are cache hot:
1701 if (sched_feat(CACHE_HOT_BUDDY
) && (&p
->se
== cfs_rq_of(&p
->se
)->next
))
1704 if (p
->sched_class
!= &fair_sched_class
)
1707 if (sysctl_sched_migration_cost
== -1)
1709 if (sysctl_sched_migration_cost
== 0)
1712 delta
= now
- p
->se
.exec_start
;
1714 return delta
< (s64
)sysctl_sched_migration_cost
;
1718 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1720 int old_cpu
= task_cpu(p
);
1721 struct rq
*old_rq
= cpu_rq(old_cpu
), *new_rq
= cpu_rq(new_cpu
);
1722 struct cfs_rq
*old_cfsrq
= task_cfs_rq(p
),
1723 *new_cfsrq
= cpu_cfs_rq(old_cfsrq
, new_cpu
);
1726 clock_offset
= old_rq
->clock
- new_rq
->clock
;
1728 #ifdef CONFIG_SCHEDSTATS
1729 if (p
->se
.wait_start
)
1730 p
->se
.wait_start
-= clock_offset
;
1731 if (p
->se
.sleep_start
)
1732 p
->se
.sleep_start
-= clock_offset
;
1733 if (p
->se
.block_start
)
1734 p
->se
.block_start
-= clock_offset
;
1735 if (old_cpu
!= new_cpu
) {
1736 schedstat_inc(p
, se
.nr_migrations
);
1737 if (task_hot(p
, old_rq
->clock
, NULL
))
1738 schedstat_inc(p
, se
.nr_forced2_migrations
);
1741 p
->se
.vruntime
-= old_cfsrq
->min_vruntime
-
1742 new_cfsrq
->min_vruntime
;
1744 __set_task_cpu(p
, new_cpu
);
1747 struct migration_req
{
1748 struct list_head list
;
1750 struct task_struct
*task
;
1753 struct completion done
;
1757 * The task's runqueue lock must be held.
1758 * Returns true if you have to wait for migration thread.
1761 migrate_task(struct task_struct
*p
, int dest_cpu
, struct migration_req
*req
)
1763 struct rq
*rq
= task_rq(p
);
1766 * If the task is not on a runqueue (and not running), then
1767 * it is sufficient to simply update the task's cpu field.
1769 if (!p
->se
.on_rq
&& !task_running(rq
, p
)) {
1770 set_task_cpu(p
, dest_cpu
);
1774 init_completion(&req
->done
);
1776 req
->dest_cpu
= dest_cpu
;
1777 list_add(&req
->list
, &rq
->migration_queue
);
1783 * wait_task_inactive - wait for a thread to unschedule.
1785 * The caller must ensure that the task *will* unschedule sometime soon,
1786 * else this function might spin for a *long* time. This function can't
1787 * be called with interrupts off, or it may introduce deadlock with
1788 * smp_call_function() if an IPI is sent by the same process we are
1789 * waiting to become inactive.
1791 void wait_task_inactive(struct task_struct
*p
)
1793 unsigned long flags
;
1799 * We do the initial early heuristics without holding
1800 * any task-queue locks at all. We'll only try to get
1801 * the runqueue lock when things look like they will
1807 * If the task is actively running on another CPU
1808 * still, just relax and busy-wait without holding
1811 * NOTE! Since we don't hold any locks, it's not
1812 * even sure that "rq" stays as the right runqueue!
1813 * But we don't care, since "task_running()" will
1814 * return false if the runqueue has changed and p
1815 * is actually now running somewhere else!
1817 while (task_running(rq
, p
))
1821 * Ok, time to look more closely! We need the rq
1822 * lock now, to be *sure*. If we're wrong, we'll
1823 * just go back and repeat.
1825 rq
= task_rq_lock(p
, &flags
);
1826 running
= task_running(rq
, p
);
1827 on_rq
= p
->se
.on_rq
;
1828 task_rq_unlock(rq
, &flags
);
1831 * Was it really running after all now that we
1832 * checked with the proper locks actually held?
1834 * Oops. Go back and try again..
1836 if (unlikely(running
)) {
1842 * It's not enough that it's not actively running,
1843 * it must be off the runqueue _entirely_, and not
1846 * So if it wa still runnable (but just not actively
1847 * running right now), it's preempted, and we should
1848 * yield - it could be a while.
1850 if (unlikely(on_rq
)) {
1851 schedule_timeout_uninterruptible(1);
1856 * Ahh, all good. It wasn't running, and it wasn't
1857 * runnable, which means that it will never become
1858 * running in the future either. We're all done!
1865 * kick_process - kick a running thread to enter/exit the kernel
1866 * @p: the to-be-kicked thread
1868 * Cause a process which is running on another CPU to enter
1869 * kernel-mode, without any delay. (to get signals handled.)
1871 * NOTE: this function doesnt have to take the runqueue lock,
1872 * because all it wants to ensure is that the remote task enters
1873 * the kernel. If the IPI races and the task has been migrated
1874 * to another CPU then no harm is done and the purpose has been
1877 void kick_process(struct task_struct
*p
)
1883 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1884 smp_send_reschedule(cpu
);
1889 * Return a low guess at the load of a migration-source cpu weighted
1890 * according to the scheduling class and "nice" value.
1892 * We want to under-estimate the load of migration sources, to
1893 * balance conservatively.
1895 static unsigned long source_load(int cpu
, int type
)
1897 struct rq
*rq
= cpu_rq(cpu
);
1898 unsigned long total
= weighted_cpuload(cpu
);
1903 return min(rq
->cpu_load
[type
-1], total
);
1907 * Return a high guess at the load of a migration-target cpu weighted
1908 * according to the scheduling class and "nice" value.
1910 static unsigned long target_load(int cpu
, int type
)
1912 struct rq
*rq
= cpu_rq(cpu
);
1913 unsigned long total
= weighted_cpuload(cpu
);
1918 return max(rq
->cpu_load
[type
-1], total
);
1922 * Return the average load per task on the cpu's run queue
1924 static unsigned long cpu_avg_load_per_task(int cpu
)
1926 struct rq
*rq
= cpu_rq(cpu
);
1927 unsigned long total
= weighted_cpuload(cpu
);
1928 unsigned long n
= rq
->nr_running
;
1930 return n
? total
/ n
: SCHED_LOAD_SCALE
;
1934 * find_idlest_group finds and returns the least busy CPU group within the
1937 static struct sched_group
*
1938 find_idlest_group(struct sched_domain
*sd
, struct task_struct
*p
, int this_cpu
)
1940 struct sched_group
*idlest
= NULL
, *this = NULL
, *group
= sd
->groups
;
1941 unsigned long min_load
= ULONG_MAX
, this_load
= 0;
1942 int load_idx
= sd
->forkexec_idx
;
1943 int imbalance
= 100 + (sd
->imbalance_pct
-100)/2;
1946 unsigned long load
, avg_load
;
1950 /* Skip over this group if it has no CPUs allowed */
1951 if (!cpus_intersects(group
->cpumask
, p
->cpus_allowed
))
1954 local_group
= cpu_isset(this_cpu
, group
->cpumask
);
1956 /* Tally up the load of all CPUs in the group */
1959 for_each_cpu_mask(i
, group
->cpumask
) {
1960 /* Bias balancing toward cpus of our domain */
1962 load
= source_load(i
, load_idx
);
1964 load
= target_load(i
, load_idx
);
1969 /* Adjust by relative CPU power of the group */
1970 avg_load
= sg_div_cpu_power(group
,
1971 avg_load
* SCHED_LOAD_SCALE
);
1974 this_load
= avg_load
;
1976 } else if (avg_load
< min_load
) {
1977 min_load
= avg_load
;
1980 } while (group
= group
->next
, group
!= sd
->groups
);
1982 if (!idlest
|| 100*this_load
< imbalance
*min_load
)
1988 * find_idlest_cpu - find the idlest cpu among the cpus in group.
1991 find_idlest_cpu(struct sched_group
*group
, struct task_struct
*p
, int this_cpu
,
1994 unsigned long load
, min_load
= ULONG_MAX
;
1998 /* Traverse only the allowed CPUs */
1999 cpus_and(*tmp
, group
->cpumask
, p
->cpus_allowed
);
2001 for_each_cpu_mask(i
, *tmp
) {
2002 load
= weighted_cpuload(i
);
2004 if (load
< min_load
|| (load
== min_load
&& i
== this_cpu
)) {
2014 * sched_balance_self: balance the current task (running on cpu) in domains
2015 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
2018 * Balance, ie. select the least loaded group.
2020 * Returns the target CPU number, or the same CPU if no balancing is needed.
2022 * preempt must be disabled.
2024 static int sched_balance_self(int cpu
, int flag
)
2026 struct task_struct
*t
= current
;
2027 struct sched_domain
*tmp
, *sd
= NULL
;
2029 for_each_domain(cpu
, tmp
) {
2031 * If power savings logic is enabled for a domain, stop there.
2033 if (tmp
->flags
& SD_POWERSAVINGS_BALANCE
)
2035 if (tmp
->flags
& flag
)
2040 cpumask_t span
, tmpmask
;
2041 struct sched_group
*group
;
2042 int new_cpu
, weight
;
2044 if (!(sd
->flags
& flag
)) {
2050 group
= find_idlest_group(sd
, t
, cpu
);
2056 new_cpu
= find_idlest_cpu(group
, t
, cpu
, &tmpmask
);
2057 if (new_cpu
== -1 || new_cpu
== cpu
) {
2058 /* Now try balancing at a lower domain level of cpu */
2063 /* Now try balancing at a lower domain level of new_cpu */
2066 weight
= cpus_weight(span
);
2067 for_each_domain(cpu
, tmp
) {
2068 if (weight
<= cpus_weight(tmp
->span
))
2070 if (tmp
->flags
& flag
)
2073 /* while loop will break here if sd == NULL */
2079 #endif /* CONFIG_SMP */
2082 * try_to_wake_up - wake up a thread
2083 * @p: the to-be-woken-up thread
2084 * @state: the mask of task states that can be woken
2085 * @sync: do a synchronous wakeup?
2087 * Put it on the run-queue if it's not already there. The "current"
2088 * thread is always on the run-queue (except when the actual
2089 * re-schedule is in progress), and as such you're allowed to do
2090 * the simpler "current->state = TASK_RUNNING" to mark yourself
2091 * runnable without the overhead of this.
2093 * returns failure only if the task is already active.
2095 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
, int sync
)
2097 int cpu
, orig_cpu
, this_cpu
, success
= 0;
2098 unsigned long flags
;
2102 if (!sched_feat(SYNC_WAKEUPS
))
2106 rq
= task_rq_lock(p
, &flags
);
2107 old_state
= p
->state
;
2108 if (!(old_state
& state
))
2116 this_cpu
= smp_processor_id();
2119 if (unlikely(task_running(rq
, p
)))
2122 cpu
= p
->sched_class
->select_task_rq(p
, sync
);
2123 if (cpu
!= orig_cpu
) {
2124 set_task_cpu(p
, cpu
);
2125 task_rq_unlock(rq
, &flags
);
2126 /* might preempt at this point */
2127 rq
= task_rq_lock(p
, &flags
);
2128 old_state
= p
->state
;
2129 if (!(old_state
& state
))
2134 this_cpu
= smp_processor_id();
2138 #ifdef CONFIG_SCHEDSTATS
2139 schedstat_inc(rq
, ttwu_count
);
2140 if (cpu
== this_cpu
)
2141 schedstat_inc(rq
, ttwu_local
);
2143 struct sched_domain
*sd
;
2144 for_each_domain(this_cpu
, sd
) {
2145 if (cpu_isset(cpu
, sd
->span
)) {
2146 schedstat_inc(sd
, ttwu_wake_remote
);
2154 #endif /* CONFIG_SMP */
2155 schedstat_inc(p
, se
.nr_wakeups
);
2157 schedstat_inc(p
, se
.nr_wakeups_sync
);
2158 if (orig_cpu
!= cpu
)
2159 schedstat_inc(p
, se
.nr_wakeups_migrate
);
2160 if (cpu
== this_cpu
)
2161 schedstat_inc(p
, se
.nr_wakeups_local
);
2163 schedstat_inc(p
, se
.nr_wakeups_remote
);
2164 update_rq_clock(rq
);
2165 activate_task(rq
, p
, 1);
2169 trace_mark(kernel_sched_wakeup
,
2170 "pid %d state %ld ## rq %p task %p rq->curr %p",
2171 p
->pid
, p
->state
, rq
, p
, rq
->curr
);
2172 check_preempt_curr(rq
, p
);
2174 p
->state
= TASK_RUNNING
;
2176 if (p
->sched_class
->task_wake_up
)
2177 p
->sched_class
->task_wake_up(rq
, p
);
2180 task_rq_unlock(rq
, &flags
);
2185 int wake_up_process(struct task_struct
*p
)
2187 return try_to_wake_up(p
, TASK_ALL
, 0);
2189 EXPORT_SYMBOL(wake_up_process
);
2191 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2193 return try_to_wake_up(p
, state
, 0);
2197 * Perform scheduler related setup for a newly forked process p.
2198 * p is forked by current.
2200 * __sched_fork() is basic setup used by init_idle() too:
2202 static void __sched_fork(struct task_struct
*p
)
2204 p
->se
.exec_start
= 0;
2205 p
->se
.sum_exec_runtime
= 0;
2206 p
->se
.prev_sum_exec_runtime
= 0;
2207 p
->se
.last_wakeup
= 0;
2208 p
->se
.avg_overlap
= 0;
2210 #ifdef CONFIG_SCHEDSTATS
2211 p
->se
.wait_start
= 0;
2212 p
->se
.sum_sleep_runtime
= 0;
2213 p
->se
.sleep_start
= 0;
2214 p
->se
.block_start
= 0;
2215 p
->se
.sleep_max
= 0;
2216 p
->se
.block_max
= 0;
2218 p
->se
.slice_max
= 0;
2222 INIT_LIST_HEAD(&p
->rt
.run_list
);
2224 INIT_LIST_HEAD(&p
->se
.group_node
);
2226 #ifdef CONFIG_PREEMPT_NOTIFIERS
2227 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2231 * We mark the process as running here, but have not actually
2232 * inserted it onto the runqueue yet. This guarantees that
2233 * nobody will actually run it, and a signal or other external
2234 * event cannot wake it up and insert it on the runqueue either.
2236 p
->state
= TASK_RUNNING
;
2240 * fork()/clone()-time setup:
2242 void sched_fork(struct task_struct
*p
, int clone_flags
)
2244 int cpu
= get_cpu();
2249 cpu
= sched_balance_self(cpu
, SD_BALANCE_FORK
);
2251 set_task_cpu(p
, cpu
);
2254 * Make sure we do not leak PI boosting priority to the child:
2256 p
->prio
= current
->normal_prio
;
2257 if (!rt_prio(p
->prio
))
2258 p
->sched_class
= &fair_sched_class
;
2260 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2261 if (likely(sched_info_on()))
2262 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2264 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2267 #ifdef CONFIG_PREEMPT
2268 /* Want to start with kernel preemption disabled. */
2269 task_thread_info(p
)->preempt_count
= 1;
2275 * wake_up_new_task - wake up a newly created task for the first time.
2277 * This function will do some initial scheduler statistics housekeeping
2278 * that must be done for every newly created context, then puts the task
2279 * on the runqueue and wakes it.
2281 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2283 unsigned long flags
;
2286 rq
= task_rq_lock(p
, &flags
);
2287 BUG_ON(p
->state
!= TASK_RUNNING
);
2288 update_rq_clock(rq
);
2290 p
->prio
= effective_prio(p
);
2292 if (!p
->sched_class
->task_new
|| !current
->se
.on_rq
) {
2293 activate_task(rq
, p
, 0);
2296 * Let the scheduling class do new task startup
2297 * management (if any):
2299 p
->sched_class
->task_new(rq
, p
);
2300 inc_nr_running(p
, rq
);
2302 trace_mark(kernel_sched_wakeup_new
,
2303 "pid %d state %ld ## rq %p task %p rq->curr %p",
2304 p
->pid
, p
->state
, rq
, p
, rq
->curr
);
2305 check_preempt_curr(rq
, p
);
2307 if (p
->sched_class
->task_wake_up
)
2308 p
->sched_class
->task_wake_up(rq
, p
);
2310 task_rq_unlock(rq
, &flags
);
2313 #ifdef CONFIG_PREEMPT_NOTIFIERS
2316 * preempt_notifier_register - tell me when current is being being preempted & rescheduled
2317 * @notifier: notifier struct to register
2319 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2321 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2323 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2326 * preempt_notifier_unregister - no longer interested in preemption notifications
2327 * @notifier: notifier struct to unregister
2329 * This is safe to call from within a preemption notifier.
2331 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2333 hlist_del(¬ifier
->link
);
2335 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2337 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2339 struct preempt_notifier
*notifier
;
2340 struct hlist_node
*node
;
2342 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2343 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2347 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2348 struct task_struct
*next
)
2350 struct preempt_notifier
*notifier
;
2351 struct hlist_node
*node
;
2353 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2354 notifier
->ops
->sched_out(notifier
, next
);
2359 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2364 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2365 struct task_struct
*next
)
2372 * prepare_task_switch - prepare to switch tasks
2373 * @rq: the runqueue preparing to switch
2374 * @prev: the current task that is being switched out
2375 * @next: the task we are going to switch to.
2377 * This is called with the rq lock held and interrupts off. It must
2378 * be paired with a subsequent finish_task_switch after the context
2381 * prepare_task_switch sets up locking and calls architecture specific
2385 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2386 struct task_struct
*next
)
2388 fire_sched_out_preempt_notifiers(prev
, next
);
2389 prepare_lock_switch(rq
, next
);
2390 prepare_arch_switch(next
);
2394 * finish_task_switch - clean up after a task-switch
2395 * @rq: runqueue associated with task-switch
2396 * @prev: the thread we just switched away from.
2398 * finish_task_switch must be called after the context switch, paired
2399 * with a prepare_task_switch call before the context switch.
2400 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2401 * and do any other architecture-specific cleanup actions.
2403 * Note that we may have delayed dropping an mm in context_switch(). If
2404 * so, we finish that here outside of the runqueue lock. (Doing it
2405 * with the lock held can cause deadlocks; see schedule() for
2408 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2409 __releases(rq
->lock
)
2411 struct mm_struct
*mm
= rq
->prev_mm
;
2417 * A task struct has one reference for the use as "current".
2418 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2419 * schedule one last time. The schedule call will never return, and
2420 * the scheduled task must drop that reference.
2421 * The test for TASK_DEAD must occur while the runqueue locks are
2422 * still held, otherwise prev could be scheduled on another cpu, die
2423 * there before we look at prev->state, and then the reference would
2425 * Manfred Spraul <manfred@colorfullife.com>
2427 prev_state
= prev
->state
;
2428 finish_arch_switch(prev
);
2429 finish_lock_switch(rq
, prev
);
2431 if (current
->sched_class
->post_schedule
)
2432 current
->sched_class
->post_schedule(rq
);
2435 fire_sched_in_preempt_notifiers(current
);
2438 if (unlikely(prev_state
== TASK_DEAD
)) {
2440 * Remove function-return probe instances associated with this
2441 * task and put them back on the free list.
2443 kprobe_flush_task(prev
);
2444 put_task_struct(prev
);
2449 * schedule_tail - first thing a freshly forked thread must call.
2450 * @prev: the thread we just switched away from.
2452 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2453 __releases(rq
->lock
)
2455 struct rq
*rq
= this_rq();
2457 finish_task_switch(rq
, prev
);
2458 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2459 /* In this case, finish_task_switch does not reenable preemption */
2462 if (current
->set_child_tid
)
2463 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2467 * context_switch - switch to the new MM and the new
2468 * thread's register state.
2471 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2472 struct task_struct
*next
)
2474 struct mm_struct
*mm
, *oldmm
;
2476 prepare_task_switch(rq
, prev
, next
);
2477 trace_mark(kernel_sched_schedule
,
2478 "prev_pid %d next_pid %d prev_state %ld "
2479 "## rq %p prev %p next %p",
2480 prev
->pid
, next
->pid
, prev
->state
,
2483 oldmm
= prev
->active_mm
;
2485 * For paravirt, this is coupled with an exit in switch_to to
2486 * combine the page table reload and the switch backend into
2489 arch_enter_lazy_cpu_mode();
2491 if (unlikely(!mm
)) {
2492 next
->active_mm
= oldmm
;
2493 atomic_inc(&oldmm
->mm_count
);
2494 enter_lazy_tlb(oldmm
, next
);
2496 switch_mm(oldmm
, mm
, next
);
2498 if (unlikely(!prev
->mm
)) {
2499 prev
->active_mm
= NULL
;
2500 rq
->prev_mm
= oldmm
;
2503 * Since the runqueue lock will be released by the next
2504 * task (which is an invalid locking op but in the case
2505 * of the scheduler it's an obvious special-case), so we
2506 * do an early lockdep release here:
2508 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2509 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2512 /* Here we just switch the register state and the stack. */
2513 switch_to(prev
, next
, prev
);
2517 * this_rq must be evaluated again because prev may have moved
2518 * CPUs since it called schedule(), thus the 'rq' on its stack
2519 * frame will be invalid.
2521 finish_task_switch(this_rq(), prev
);
2525 * nr_running, nr_uninterruptible and nr_context_switches:
2527 * externally visible scheduler statistics: current number of runnable
2528 * threads, current number of uninterruptible-sleeping threads, total
2529 * number of context switches performed since bootup.
2531 unsigned long nr_running(void)
2533 unsigned long i
, sum
= 0;
2535 for_each_online_cpu(i
)
2536 sum
+= cpu_rq(i
)->nr_running
;
2541 unsigned long nr_uninterruptible(void)
2543 unsigned long i
, sum
= 0;
2545 for_each_possible_cpu(i
)
2546 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2549 * Since we read the counters lockless, it might be slightly
2550 * inaccurate. Do not allow it to go below zero though:
2552 if (unlikely((long)sum
< 0))
2558 unsigned long long nr_context_switches(void)
2561 unsigned long long sum
= 0;
2563 for_each_possible_cpu(i
)
2564 sum
+= cpu_rq(i
)->nr_switches
;
2569 unsigned long nr_iowait(void)
2571 unsigned long i
, sum
= 0;
2573 for_each_possible_cpu(i
)
2574 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2579 unsigned long nr_active(void)
2581 unsigned long i
, running
= 0, uninterruptible
= 0;
2583 for_each_online_cpu(i
) {
2584 running
+= cpu_rq(i
)->nr_running
;
2585 uninterruptible
+= cpu_rq(i
)->nr_uninterruptible
;
2588 if (unlikely((long)uninterruptible
< 0))
2589 uninterruptible
= 0;
2591 return running
+ uninterruptible
;
2595 * Update rq->cpu_load[] statistics. This function is usually called every
2596 * scheduler tick (TICK_NSEC).
2598 static void update_cpu_load(struct rq
*this_rq
)
2600 unsigned long this_load
= this_rq
->load
.weight
;
2603 this_rq
->nr_load_updates
++;
2605 /* Update our load: */
2606 for (i
= 0, scale
= 1; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
2607 unsigned long old_load
, new_load
;
2609 /* scale is effectively 1 << i now, and >> i divides by scale */
2611 old_load
= this_rq
->cpu_load
[i
];
2612 new_load
= this_load
;
2614 * Round up the averaging division if load is increasing. This
2615 * prevents us from getting stuck on 9 if the load is 10, for
2618 if (new_load
> old_load
)
2619 new_load
+= scale
-1;
2620 this_rq
->cpu_load
[i
] = (old_load
*(scale
-1) + new_load
) >> i
;
2627 * double_rq_lock - safely lock two runqueues
2629 * Note this does not disable interrupts like task_rq_lock,
2630 * you need to do so manually before calling.
2632 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
2633 __acquires(rq1
->lock
)
2634 __acquires(rq2
->lock
)
2636 BUG_ON(!irqs_disabled());
2638 spin_lock(&rq1
->lock
);
2639 __acquire(rq2
->lock
); /* Fake it out ;) */
2642 spin_lock(&rq1
->lock
);
2643 spin_lock(&rq2
->lock
);
2645 spin_lock(&rq2
->lock
);
2646 spin_lock(&rq1
->lock
);
2649 update_rq_clock(rq1
);
2650 update_rq_clock(rq2
);
2654 * double_rq_unlock - safely unlock two runqueues
2656 * Note this does not restore interrupts like task_rq_unlock,
2657 * you need to do so manually after calling.
2659 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
2660 __releases(rq1
->lock
)
2661 __releases(rq2
->lock
)
2663 spin_unlock(&rq1
->lock
);
2665 spin_unlock(&rq2
->lock
);
2667 __release(rq2
->lock
);
2671 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
2673 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
2674 __releases(this_rq
->lock
)
2675 __acquires(busiest
->lock
)
2676 __acquires(this_rq
->lock
)
2680 if (unlikely(!irqs_disabled())) {
2681 /* printk() doesn't work good under rq->lock */
2682 spin_unlock(&this_rq
->lock
);
2685 if (unlikely(!spin_trylock(&busiest
->lock
))) {
2686 if (busiest
< this_rq
) {
2687 spin_unlock(&this_rq
->lock
);
2688 spin_lock(&busiest
->lock
);
2689 spin_lock(&this_rq
->lock
);
2692 spin_lock(&busiest
->lock
);
2698 * If dest_cpu is allowed for this process, migrate the task to it.
2699 * This is accomplished by forcing the cpu_allowed mask to only
2700 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
2701 * the cpu_allowed mask is restored.
2703 static void sched_migrate_task(struct task_struct
*p
, int dest_cpu
)
2705 struct migration_req req
;
2706 unsigned long flags
;
2709 rq
= task_rq_lock(p
, &flags
);
2710 if (!cpu_isset(dest_cpu
, p
->cpus_allowed
)
2711 || unlikely(cpu_is_offline(dest_cpu
)))
2714 /* force the process onto the specified CPU */
2715 if (migrate_task(p
, dest_cpu
, &req
)) {
2716 /* Need to wait for migration thread (might exit: take ref). */
2717 struct task_struct
*mt
= rq
->migration_thread
;
2719 get_task_struct(mt
);
2720 task_rq_unlock(rq
, &flags
);
2721 wake_up_process(mt
);
2722 put_task_struct(mt
);
2723 wait_for_completion(&req
.done
);
2728 task_rq_unlock(rq
, &flags
);
2732 * sched_exec - execve() is a valuable balancing opportunity, because at
2733 * this point the task has the smallest effective memory and cache footprint.
2735 void sched_exec(void)
2737 int new_cpu
, this_cpu
= get_cpu();
2738 new_cpu
= sched_balance_self(this_cpu
, SD_BALANCE_EXEC
);
2740 if (new_cpu
!= this_cpu
)
2741 sched_migrate_task(current
, new_cpu
);
2745 * pull_task - move a task from a remote runqueue to the local runqueue.
2746 * Both runqueues must be locked.
2748 static void pull_task(struct rq
*src_rq
, struct task_struct
*p
,
2749 struct rq
*this_rq
, int this_cpu
)
2751 deactivate_task(src_rq
, p
, 0);
2752 set_task_cpu(p
, this_cpu
);
2753 activate_task(this_rq
, p
, 0);
2755 * Note that idle threads have a prio of MAX_PRIO, for this test
2756 * to be always true for them.
2758 check_preempt_curr(this_rq
, p
);
2762 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
2765 int can_migrate_task(struct task_struct
*p
, struct rq
*rq
, int this_cpu
,
2766 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2770 * We do not migrate tasks that are:
2771 * 1) running (obviously), or
2772 * 2) cannot be migrated to this CPU due to cpus_allowed, or
2773 * 3) are cache-hot on their current CPU.
2775 if (!cpu_isset(this_cpu
, p
->cpus_allowed
)) {
2776 schedstat_inc(p
, se
.nr_failed_migrations_affine
);
2781 if (task_running(rq
, p
)) {
2782 schedstat_inc(p
, se
.nr_failed_migrations_running
);
2787 * Aggressive migration if:
2788 * 1) task is cache cold, or
2789 * 2) too many balance attempts have failed.
2792 if (!task_hot(p
, rq
->clock
, sd
) ||
2793 sd
->nr_balance_failed
> sd
->cache_nice_tries
) {
2794 #ifdef CONFIG_SCHEDSTATS
2795 if (task_hot(p
, rq
->clock
, sd
)) {
2796 schedstat_inc(sd
, lb_hot_gained
[idle
]);
2797 schedstat_inc(p
, se
.nr_forced_migrations
);
2803 if (task_hot(p
, rq
->clock
, sd
)) {
2804 schedstat_inc(p
, se
.nr_failed_migrations_hot
);
2810 static unsigned long
2811 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2812 unsigned long max_load_move
, struct sched_domain
*sd
,
2813 enum cpu_idle_type idle
, int *all_pinned
,
2814 int *this_best_prio
, struct rq_iterator
*iterator
)
2816 int loops
= 0, pulled
= 0, pinned
= 0, skip_for_load
;
2817 struct task_struct
*p
;
2818 long rem_load_move
= max_load_move
;
2820 if (max_load_move
== 0)
2826 * Start the load-balancing iterator:
2828 p
= iterator
->start(iterator
->arg
);
2830 if (!p
|| loops
++ > sysctl_sched_nr_migrate
)
2833 * To help distribute high priority tasks across CPUs we don't
2834 * skip a task if it will be the highest priority task (i.e. smallest
2835 * prio value) on its new queue regardless of its load weight
2837 skip_for_load
= (p
->se
.load
.weight
>> 1) > rem_load_move
+
2838 SCHED_LOAD_SCALE_FUZZ
;
2839 if ((skip_for_load
&& p
->prio
>= *this_best_prio
) ||
2840 !can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
2841 p
= iterator
->next(iterator
->arg
);
2845 pull_task(busiest
, p
, this_rq
, this_cpu
);
2847 rem_load_move
-= p
->se
.load
.weight
;
2850 * We only want to steal up to the prescribed amount of weighted load.
2852 if (rem_load_move
> 0) {
2853 if (p
->prio
< *this_best_prio
)
2854 *this_best_prio
= p
->prio
;
2855 p
= iterator
->next(iterator
->arg
);
2860 * Right now, this is one of only two places pull_task() is called,
2861 * so we can safely collect pull_task() stats here rather than
2862 * inside pull_task().
2864 schedstat_add(sd
, lb_gained
[idle
], pulled
);
2867 *all_pinned
= pinned
;
2869 return max_load_move
- rem_load_move
;
2873 * move_tasks tries to move up to max_load_move weighted load from busiest to
2874 * this_rq, as part of a balancing operation within domain "sd".
2875 * Returns 1 if successful and 0 otherwise.
2877 * Called with both runqueues locked.
2879 static int move_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2880 unsigned long max_load_move
,
2881 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2884 const struct sched_class
*class = sched_class_highest
;
2885 unsigned long total_load_moved
= 0;
2886 int this_best_prio
= this_rq
->curr
->prio
;
2890 class->load_balance(this_rq
, this_cpu
, busiest
,
2891 max_load_move
- total_load_moved
,
2892 sd
, idle
, all_pinned
, &this_best_prio
);
2893 class = class->next
;
2894 } while (class && max_load_move
> total_load_moved
);
2896 return total_load_moved
> 0;
2900 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2901 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2902 struct rq_iterator
*iterator
)
2904 struct task_struct
*p
= iterator
->start(iterator
->arg
);
2908 if (can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
2909 pull_task(busiest
, p
, this_rq
, this_cpu
);
2911 * Right now, this is only the second place pull_task()
2912 * is called, so we can safely collect pull_task()
2913 * stats here rather than inside pull_task().
2915 schedstat_inc(sd
, lb_gained
[idle
]);
2919 p
= iterator
->next(iterator
->arg
);
2926 * move_one_task tries to move exactly one task from busiest to this_rq, as
2927 * part of active balancing operations within "domain".
2928 * Returns 1 if successful and 0 otherwise.
2930 * Called with both runqueues locked.
2932 static int move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2933 struct sched_domain
*sd
, enum cpu_idle_type idle
)
2935 const struct sched_class
*class;
2937 for (class = sched_class_highest
; class; class = class->next
)
2938 if (class->move_one_task(this_rq
, this_cpu
, busiest
, sd
, idle
))
2945 * find_busiest_group finds and returns the busiest CPU group within the
2946 * domain. It calculates and returns the amount of weighted load which
2947 * should be moved to restore balance via the imbalance parameter.
2949 static struct sched_group
*
2950 find_busiest_group(struct sched_domain
*sd
, int this_cpu
,
2951 unsigned long *imbalance
, enum cpu_idle_type idle
,
2952 int *sd_idle
, const cpumask_t
*cpus
, int *balance
)
2954 struct sched_group
*busiest
= NULL
, *this = NULL
, *group
= sd
->groups
;
2955 unsigned long max_load
, avg_load
, total_load
, this_load
, total_pwr
;
2956 unsigned long max_pull
;
2957 unsigned long busiest_load_per_task
, busiest_nr_running
;
2958 unsigned long this_load_per_task
, this_nr_running
;
2959 int load_idx
, group_imb
= 0;
2960 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
2961 int power_savings_balance
= 1;
2962 unsigned long leader_nr_running
= 0, min_load_per_task
= 0;
2963 unsigned long min_nr_running
= ULONG_MAX
;
2964 struct sched_group
*group_min
= NULL
, *group_leader
= NULL
;
2967 max_load
= this_load
= total_load
= total_pwr
= 0;
2968 busiest_load_per_task
= busiest_nr_running
= 0;
2969 this_load_per_task
= this_nr_running
= 0;
2970 if (idle
== CPU_NOT_IDLE
)
2971 load_idx
= sd
->busy_idx
;
2972 else if (idle
== CPU_NEWLY_IDLE
)
2973 load_idx
= sd
->newidle_idx
;
2975 load_idx
= sd
->idle_idx
;
2978 unsigned long load
, group_capacity
, max_cpu_load
, min_cpu_load
;
2981 int __group_imb
= 0;
2982 unsigned int balance_cpu
= -1, first_idle_cpu
= 0;
2983 unsigned long sum_nr_running
, sum_weighted_load
;
2985 local_group
= cpu_isset(this_cpu
, group
->cpumask
);
2988 balance_cpu
= first_cpu(group
->cpumask
);
2990 /* Tally up the load of all CPUs in the group */
2991 sum_weighted_load
= sum_nr_running
= avg_load
= 0;
2993 min_cpu_load
= ~0UL;
2995 for_each_cpu_mask(i
, group
->cpumask
) {
2998 if (!cpu_isset(i
, *cpus
))
3003 if (*sd_idle
&& rq
->nr_running
)
3006 /* Bias balancing toward cpus of our domain */
3008 if (idle_cpu(i
) && !first_idle_cpu
) {
3013 load
= target_load(i
, load_idx
);
3015 load
= source_load(i
, load_idx
);
3016 if (load
> max_cpu_load
)
3017 max_cpu_load
= load
;
3018 if (min_cpu_load
> load
)
3019 min_cpu_load
= load
;
3023 sum_nr_running
+= rq
->nr_running
;
3024 sum_weighted_load
+= weighted_cpuload(i
);
3028 * First idle cpu or the first cpu(busiest) in this sched group
3029 * is eligible for doing load balancing at this and above
3030 * domains. In the newly idle case, we will allow all the cpu's
3031 * to do the newly idle load balance.
3033 if (idle
!= CPU_NEWLY_IDLE
&& local_group
&&
3034 balance_cpu
!= this_cpu
&& balance
) {
3039 total_load
+= avg_load
;
3040 total_pwr
+= group
->__cpu_power
;
3042 /* Adjust by relative CPU power of the group */
3043 avg_load
= sg_div_cpu_power(group
,
3044 avg_load
* SCHED_LOAD_SCALE
);
3046 if ((max_cpu_load
- min_cpu_load
) > SCHED_LOAD_SCALE
)
3049 group_capacity
= group
->__cpu_power
/ SCHED_LOAD_SCALE
;
3052 this_load
= avg_load
;
3054 this_nr_running
= sum_nr_running
;
3055 this_load_per_task
= sum_weighted_load
;
3056 } else if (avg_load
> max_load
&&
3057 (sum_nr_running
> group_capacity
|| __group_imb
)) {
3058 max_load
= avg_load
;
3060 busiest_nr_running
= sum_nr_running
;
3061 busiest_load_per_task
= sum_weighted_load
;
3062 group_imb
= __group_imb
;
3065 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3067 * Busy processors will not participate in power savings
3070 if (idle
== CPU_NOT_IDLE
||
3071 !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3075 * If the local group is idle or completely loaded
3076 * no need to do power savings balance at this domain
3078 if (local_group
&& (this_nr_running
>= group_capacity
||
3080 power_savings_balance
= 0;
3083 * If a group is already running at full capacity or idle,
3084 * don't include that group in power savings calculations
3086 if (!power_savings_balance
|| sum_nr_running
>= group_capacity
3091 * Calculate the group which has the least non-idle load.
3092 * This is the group from where we need to pick up the load
3095 if ((sum_nr_running
< min_nr_running
) ||
3096 (sum_nr_running
== min_nr_running
&&
3097 first_cpu(group
->cpumask
) <
3098 first_cpu(group_min
->cpumask
))) {
3100 min_nr_running
= sum_nr_running
;
3101 min_load_per_task
= sum_weighted_load
/
3106 * Calculate the group which is almost near its
3107 * capacity but still has some space to pick up some load
3108 * from other group and save more power
3110 if (sum_nr_running
<= group_capacity
- 1) {
3111 if (sum_nr_running
> leader_nr_running
||
3112 (sum_nr_running
== leader_nr_running
&&
3113 first_cpu(group
->cpumask
) >
3114 first_cpu(group_leader
->cpumask
))) {
3115 group_leader
= group
;
3116 leader_nr_running
= sum_nr_running
;
3121 group
= group
->next
;
3122 } while (group
!= sd
->groups
);
3124 if (!busiest
|| this_load
>= max_load
|| busiest_nr_running
== 0)
3127 avg_load
= (SCHED_LOAD_SCALE
* total_load
) / total_pwr
;
3129 if (this_load
>= avg_load
||
3130 100*max_load
<= sd
->imbalance_pct
*this_load
)
3133 busiest_load_per_task
/= busiest_nr_running
;
3135 busiest_load_per_task
= min(busiest_load_per_task
, avg_load
);
3138 * We're trying to get all the cpus to the average_load, so we don't
3139 * want to push ourselves above the average load, nor do we wish to
3140 * reduce the max loaded cpu below the average load, as either of these
3141 * actions would just result in more rebalancing later, and ping-pong
3142 * tasks around. Thus we look for the minimum possible imbalance.
3143 * Negative imbalances (*we* are more loaded than anyone else) will
3144 * be counted as no imbalance for these purposes -- we can't fix that
3145 * by pulling tasks to us. Be careful of negative numbers as they'll
3146 * appear as very large values with unsigned longs.
3148 if (max_load
<= busiest_load_per_task
)
3152 * In the presence of smp nice balancing, certain scenarios can have
3153 * max load less than avg load(as we skip the groups at or below
3154 * its cpu_power, while calculating max_load..)
3156 if (max_load
< avg_load
) {
3158 goto small_imbalance
;
3161 /* Don't want to pull so many tasks that a group would go idle */
3162 max_pull
= min(max_load
- avg_load
, max_load
- busiest_load_per_task
);
3164 /* How much load to actually move to equalise the imbalance */
3165 *imbalance
= min(max_pull
* busiest
->__cpu_power
,
3166 (avg_load
- this_load
) * this->__cpu_power
)
3170 * if *imbalance is less than the average load per runnable task
3171 * there is no gaurantee that any tasks will be moved so we'll have
3172 * a think about bumping its value to force at least one task to be
3175 if (*imbalance
< busiest_load_per_task
) {
3176 unsigned long tmp
, pwr_now
, pwr_move
;
3180 pwr_move
= pwr_now
= 0;
3182 if (this_nr_running
) {
3183 this_load_per_task
/= this_nr_running
;
3184 if (busiest_load_per_task
> this_load_per_task
)
3187 this_load_per_task
= SCHED_LOAD_SCALE
;
3189 if (max_load
- this_load
+ SCHED_LOAD_SCALE_FUZZ
>=
3190 busiest_load_per_task
* imbn
) {
3191 *imbalance
= busiest_load_per_task
;
3196 * OK, we don't have enough imbalance to justify moving tasks,
3197 * however we may be able to increase total CPU power used by
3201 pwr_now
+= busiest
->__cpu_power
*
3202 min(busiest_load_per_task
, max_load
);
3203 pwr_now
+= this->__cpu_power
*
3204 min(this_load_per_task
, this_load
);
3205 pwr_now
/= SCHED_LOAD_SCALE
;
3207 /* Amount of load we'd subtract */
3208 tmp
= sg_div_cpu_power(busiest
,
3209 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3211 pwr_move
+= busiest
->__cpu_power
*
3212 min(busiest_load_per_task
, max_load
- tmp
);
3214 /* Amount of load we'd add */
3215 if (max_load
* busiest
->__cpu_power
<
3216 busiest_load_per_task
* SCHED_LOAD_SCALE
)
3217 tmp
= sg_div_cpu_power(this,
3218 max_load
* busiest
->__cpu_power
);
3220 tmp
= sg_div_cpu_power(this,
3221 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3222 pwr_move
+= this->__cpu_power
*
3223 min(this_load_per_task
, this_load
+ tmp
);
3224 pwr_move
/= SCHED_LOAD_SCALE
;
3226 /* Move if we gain throughput */
3227 if (pwr_move
> pwr_now
)
3228 *imbalance
= busiest_load_per_task
;
3234 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3235 if (idle
== CPU_NOT_IDLE
|| !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3238 if (this == group_leader
&& group_leader
!= group_min
) {
3239 *imbalance
= min_load_per_task
;
3249 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3252 find_busiest_queue(struct sched_group
*group
, enum cpu_idle_type idle
,
3253 unsigned long imbalance
, const cpumask_t
*cpus
)
3255 struct rq
*busiest
= NULL
, *rq
;
3256 unsigned long max_load
= 0;
3259 for_each_cpu_mask(i
, group
->cpumask
) {
3262 if (!cpu_isset(i
, *cpus
))
3266 wl
= weighted_cpuload(i
);
3268 if (rq
->nr_running
== 1 && wl
> imbalance
)
3271 if (wl
> max_load
) {
3281 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
3282 * so long as it is large enough.
3284 #define MAX_PINNED_INTERVAL 512
3287 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3288 * tasks if there is an imbalance.
3290 static int load_balance(int this_cpu
, struct rq
*this_rq
,
3291 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3292 int *balance
, cpumask_t
*cpus
)
3294 int ld_moved
, all_pinned
= 0, active_balance
= 0, sd_idle
= 0;
3295 struct sched_group
*group
;
3296 unsigned long imbalance
;
3298 unsigned long flags
;
3303 * When power savings policy is enabled for the parent domain, idle
3304 * sibling can pick up load irrespective of busy siblings. In this case,
3305 * let the state of idle sibling percolate up as CPU_IDLE, instead of
3306 * portraying it as CPU_NOT_IDLE.
3308 if (idle
!= CPU_NOT_IDLE
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3309 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3312 schedstat_inc(sd
, lb_count
[idle
]);
3315 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, idle
, &sd_idle
,
3322 schedstat_inc(sd
, lb_nobusyg
[idle
]);
3326 busiest
= find_busiest_queue(group
, idle
, imbalance
, cpus
);
3328 schedstat_inc(sd
, lb_nobusyq
[idle
]);
3332 BUG_ON(busiest
== this_rq
);
3334 schedstat_add(sd
, lb_imbalance
[idle
], imbalance
);
3337 if (busiest
->nr_running
> 1) {
3339 * Attempt to move tasks. If find_busiest_group has found
3340 * an imbalance but busiest->nr_running <= 1, the group is
3341 * still unbalanced. ld_moved simply stays zero, so it is
3342 * correctly treated as an imbalance.
3344 local_irq_save(flags
);
3345 double_rq_lock(this_rq
, busiest
);
3346 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3347 imbalance
, sd
, idle
, &all_pinned
);
3348 double_rq_unlock(this_rq
, busiest
);
3349 local_irq_restore(flags
);
3352 * some other cpu did the load balance for us.
3354 if (ld_moved
&& this_cpu
!= smp_processor_id())
3355 resched_cpu(this_cpu
);
3357 /* All tasks on this runqueue were pinned by CPU affinity */
3358 if (unlikely(all_pinned
)) {
3359 cpu_clear(cpu_of(busiest
), *cpus
);
3360 if (!cpus_empty(*cpus
))
3367 schedstat_inc(sd
, lb_failed
[idle
]);
3368 sd
->nr_balance_failed
++;
3370 if (unlikely(sd
->nr_balance_failed
> sd
->cache_nice_tries
+2)) {
3372 spin_lock_irqsave(&busiest
->lock
, flags
);
3374 /* don't kick the migration_thread, if the curr
3375 * task on busiest cpu can't be moved to this_cpu
3377 if (!cpu_isset(this_cpu
, busiest
->curr
->cpus_allowed
)) {
3378 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3380 goto out_one_pinned
;
3383 if (!busiest
->active_balance
) {
3384 busiest
->active_balance
= 1;
3385 busiest
->push_cpu
= this_cpu
;
3388 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3390 wake_up_process(busiest
->migration_thread
);
3393 * We've kicked active balancing, reset the failure
3396 sd
->nr_balance_failed
= sd
->cache_nice_tries
+1;
3399 sd
->nr_balance_failed
= 0;
3401 if (likely(!active_balance
)) {
3402 /* We were unbalanced, so reset the balancing interval */
3403 sd
->balance_interval
= sd
->min_interval
;
3406 * If we've begun active balancing, start to back off. This
3407 * case may not be covered by the all_pinned logic if there
3408 * is only 1 task on the busy runqueue (because we don't call
3411 if (sd
->balance_interval
< sd
->max_interval
)
3412 sd
->balance_interval
*= 2;
3415 if (!ld_moved
&& !sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3416 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3421 schedstat_inc(sd
, lb_balanced
[idle
]);
3423 sd
->nr_balance_failed
= 0;
3426 /* tune up the balancing interval */
3427 if ((all_pinned
&& sd
->balance_interval
< MAX_PINNED_INTERVAL
) ||
3428 (sd
->balance_interval
< sd
->max_interval
))
3429 sd
->balance_interval
*= 2;
3431 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3432 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3438 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3439 * tasks if there is an imbalance.
3441 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
3442 * this_rq is locked.
3445 load_balance_newidle(int this_cpu
, struct rq
*this_rq
, struct sched_domain
*sd
,
3448 struct sched_group
*group
;
3449 struct rq
*busiest
= NULL
;
3450 unsigned long imbalance
;
3458 * When power savings policy is enabled for the parent domain, idle
3459 * sibling can pick up load irrespective of busy siblings. In this case,
3460 * let the state of idle sibling percolate up as IDLE, instead of
3461 * portraying it as CPU_NOT_IDLE.
3463 if (sd
->flags
& SD_SHARE_CPUPOWER
&&
3464 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3467 schedstat_inc(sd
, lb_count
[CPU_NEWLY_IDLE
]);
3469 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, CPU_NEWLY_IDLE
,
3470 &sd_idle
, cpus
, NULL
);
3472 schedstat_inc(sd
, lb_nobusyg
[CPU_NEWLY_IDLE
]);
3476 busiest
= find_busiest_queue(group
, CPU_NEWLY_IDLE
, imbalance
, cpus
);
3478 schedstat_inc(sd
, lb_nobusyq
[CPU_NEWLY_IDLE
]);
3482 BUG_ON(busiest
== this_rq
);
3484 schedstat_add(sd
, lb_imbalance
[CPU_NEWLY_IDLE
], imbalance
);
3487 if (busiest
->nr_running
> 1) {
3488 /* Attempt to move tasks */
3489 double_lock_balance(this_rq
, busiest
);
3490 /* this_rq->clock is already updated */
3491 update_rq_clock(busiest
);
3492 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3493 imbalance
, sd
, CPU_NEWLY_IDLE
,
3495 spin_unlock(&busiest
->lock
);
3497 if (unlikely(all_pinned
)) {
3498 cpu_clear(cpu_of(busiest
), *cpus
);
3499 if (!cpus_empty(*cpus
))
3505 schedstat_inc(sd
, lb_failed
[CPU_NEWLY_IDLE
]);
3506 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3507 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3510 sd
->nr_balance_failed
= 0;
3515 schedstat_inc(sd
, lb_balanced
[CPU_NEWLY_IDLE
]);
3516 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3517 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3519 sd
->nr_balance_failed
= 0;
3525 * idle_balance is called by schedule() if this_cpu is about to become
3526 * idle. Attempts to pull tasks from other CPUs.
3528 static void idle_balance(int this_cpu
, struct rq
*this_rq
)
3530 struct sched_domain
*sd
;
3531 int pulled_task
= -1;
3532 unsigned long next_balance
= jiffies
+ HZ
;
3535 for_each_domain(this_cpu
, sd
) {
3536 unsigned long interval
;
3538 if (!(sd
->flags
& SD_LOAD_BALANCE
))
3541 if (sd
->flags
& SD_BALANCE_NEWIDLE
)
3542 /* If we've pulled tasks over stop searching: */
3543 pulled_task
= load_balance_newidle(this_cpu
, this_rq
,
3546 interval
= msecs_to_jiffies(sd
->balance_interval
);
3547 if (time_after(next_balance
, sd
->last_balance
+ interval
))
3548 next_balance
= sd
->last_balance
+ interval
;
3552 if (pulled_task
|| time_after(jiffies
, this_rq
->next_balance
)) {
3554 * We are going idle. next_balance may be set based on
3555 * a busy processor. So reset next_balance.
3557 this_rq
->next_balance
= next_balance
;
3562 * active_load_balance is run by migration threads. It pushes running tasks
3563 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
3564 * running on each physical CPU where possible, and avoids physical /
3565 * logical imbalances.
3567 * Called with busiest_rq locked.
3569 static void active_load_balance(struct rq
*busiest_rq
, int busiest_cpu
)
3571 int target_cpu
= busiest_rq
->push_cpu
;
3572 struct sched_domain
*sd
;
3573 struct rq
*target_rq
;
3575 /* Is there any task to move? */
3576 if (busiest_rq
->nr_running
<= 1)
3579 target_rq
= cpu_rq(target_cpu
);
3582 * This condition is "impossible", if it occurs
3583 * we need to fix it. Originally reported by
3584 * Bjorn Helgaas on a 128-cpu setup.
3586 BUG_ON(busiest_rq
== target_rq
);
3588 /* move a task from busiest_rq to target_rq */
3589 double_lock_balance(busiest_rq
, target_rq
);
3590 update_rq_clock(busiest_rq
);
3591 update_rq_clock(target_rq
);
3593 /* Search for an sd spanning us and the target CPU. */
3594 for_each_domain(target_cpu
, sd
) {
3595 if ((sd
->flags
& SD_LOAD_BALANCE
) &&
3596 cpu_isset(busiest_cpu
, sd
->span
))
3601 schedstat_inc(sd
, alb_count
);
3603 if (move_one_task(target_rq
, target_cpu
, busiest_rq
,
3605 schedstat_inc(sd
, alb_pushed
);
3607 schedstat_inc(sd
, alb_failed
);
3609 spin_unlock(&target_rq
->lock
);
3614 atomic_t load_balancer
;
3616 } nohz ____cacheline_aligned
= {
3617 .load_balancer
= ATOMIC_INIT(-1),
3618 .cpu_mask
= CPU_MASK_NONE
,
3622 * This routine will try to nominate the ilb (idle load balancing)
3623 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
3624 * load balancing on behalf of all those cpus. If all the cpus in the system
3625 * go into this tickless mode, then there will be no ilb owner (as there is
3626 * no need for one) and all the cpus will sleep till the next wakeup event
3629 * For the ilb owner, tick is not stopped. And this tick will be used
3630 * for idle load balancing. ilb owner will still be part of
3633 * While stopping the tick, this cpu will become the ilb owner if there
3634 * is no other owner. And will be the owner till that cpu becomes busy
3635 * or if all cpus in the system stop their ticks at which point
3636 * there is no need for ilb owner.
3638 * When the ilb owner becomes busy, it nominates another owner, during the
3639 * next busy scheduler_tick()
3641 int select_nohz_load_balancer(int stop_tick
)
3643 int cpu
= smp_processor_id();
3646 cpu_set(cpu
, nohz
.cpu_mask
);
3647 cpu_rq(cpu
)->in_nohz_recently
= 1;
3650 * If we are going offline and still the leader, give up!
3652 if (cpu_is_offline(cpu
) &&
3653 atomic_read(&nohz
.load_balancer
) == cpu
) {
3654 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
3659 /* time for ilb owner also to sleep */
3660 if (cpus_weight(nohz
.cpu_mask
) == num_online_cpus()) {
3661 if (atomic_read(&nohz
.load_balancer
) == cpu
)
3662 atomic_set(&nohz
.load_balancer
, -1);
3666 if (atomic_read(&nohz
.load_balancer
) == -1) {
3667 /* make me the ilb owner */
3668 if (atomic_cmpxchg(&nohz
.load_balancer
, -1, cpu
) == -1)
3670 } else if (atomic_read(&nohz
.load_balancer
) == cpu
)
3673 if (!cpu_isset(cpu
, nohz
.cpu_mask
))
3676 cpu_clear(cpu
, nohz
.cpu_mask
);
3678 if (atomic_read(&nohz
.load_balancer
) == cpu
)
3679 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
3686 static DEFINE_SPINLOCK(balancing
);
3689 * It checks each scheduling domain to see if it is due to be balanced,
3690 * and initiates a balancing operation if so.
3692 * Balancing parameters are set up in arch_init_sched_domains.
3694 static void rebalance_domains(int cpu
, enum cpu_idle_type idle
)
3697 struct rq
*rq
= cpu_rq(cpu
);
3698 unsigned long interval
;
3699 struct sched_domain
*sd
;
3700 /* Earliest time when we have to do rebalance again */
3701 unsigned long next_balance
= jiffies
+ 60*HZ
;
3702 int update_next_balance
= 0;
3705 for_each_domain(cpu
, sd
) {
3706 if (!(sd
->flags
& SD_LOAD_BALANCE
))
3709 interval
= sd
->balance_interval
;
3710 if (idle
!= CPU_IDLE
)
3711 interval
*= sd
->busy_factor
;
3713 /* scale ms to jiffies */
3714 interval
= msecs_to_jiffies(interval
);
3715 if (unlikely(!interval
))
3717 if (interval
> HZ
*NR_CPUS
/10)
3718 interval
= HZ
*NR_CPUS
/10;
3721 if (sd
->flags
& SD_SERIALIZE
) {
3722 if (!spin_trylock(&balancing
))
3726 if (time_after_eq(jiffies
, sd
->last_balance
+ interval
)) {
3727 if (load_balance(cpu
, rq
, sd
, idle
, &balance
, &tmp
)) {
3729 * We've pulled tasks over so either we're no
3730 * longer idle, or one of our SMT siblings is
3733 idle
= CPU_NOT_IDLE
;
3735 sd
->last_balance
= jiffies
;
3737 if (sd
->flags
& SD_SERIALIZE
)
3738 spin_unlock(&balancing
);
3740 if (time_after(next_balance
, sd
->last_balance
+ interval
)) {
3741 next_balance
= sd
->last_balance
+ interval
;
3742 update_next_balance
= 1;
3746 * Stop the load balance at this level. There is another
3747 * CPU in our sched group which is doing load balancing more
3755 * next_balance will be updated only when there is a need.
3756 * When the cpu is attached to null domain for ex, it will not be
3759 if (likely(update_next_balance
))
3760 rq
->next_balance
= next_balance
;
3764 * run_rebalance_domains is triggered when needed from the scheduler tick.
3765 * In CONFIG_NO_HZ case, the idle load balance owner will do the
3766 * rebalancing for all the cpus for whom scheduler ticks are stopped.
3768 static void run_rebalance_domains(struct softirq_action
*h
)
3770 int this_cpu
= smp_processor_id();
3771 struct rq
*this_rq
= cpu_rq(this_cpu
);
3772 enum cpu_idle_type idle
= this_rq
->idle_at_tick
?
3773 CPU_IDLE
: CPU_NOT_IDLE
;
3775 rebalance_domains(this_cpu
, idle
);
3779 * If this cpu is the owner for idle load balancing, then do the
3780 * balancing on behalf of the other idle cpus whose ticks are
3783 if (this_rq
->idle_at_tick
&&
3784 atomic_read(&nohz
.load_balancer
) == this_cpu
) {
3785 cpumask_t cpus
= nohz
.cpu_mask
;
3789 cpu_clear(this_cpu
, cpus
);
3790 for_each_cpu_mask(balance_cpu
, cpus
) {
3792 * If this cpu gets work to do, stop the load balancing
3793 * work being done for other cpus. Next load
3794 * balancing owner will pick it up.
3799 rebalance_domains(balance_cpu
, CPU_IDLE
);
3801 rq
= cpu_rq(balance_cpu
);
3802 if (time_after(this_rq
->next_balance
, rq
->next_balance
))
3803 this_rq
->next_balance
= rq
->next_balance
;
3810 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
3812 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
3813 * idle load balancing owner or decide to stop the periodic load balancing,
3814 * if the whole system is idle.
3816 static inline void trigger_load_balance(struct rq
*rq
, int cpu
)
3820 * If we were in the nohz mode recently and busy at the current
3821 * scheduler tick, then check if we need to nominate new idle
3824 if (rq
->in_nohz_recently
&& !rq
->idle_at_tick
) {
3825 rq
->in_nohz_recently
= 0;
3827 if (atomic_read(&nohz
.load_balancer
) == cpu
) {
3828 cpu_clear(cpu
, nohz
.cpu_mask
);
3829 atomic_set(&nohz
.load_balancer
, -1);
3832 if (atomic_read(&nohz
.load_balancer
) == -1) {
3834 * simple selection for now: Nominate the
3835 * first cpu in the nohz list to be the next
3838 * TBD: Traverse the sched domains and nominate
3839 * the nearest cpu in the nohz.cpu_mask.
3841 int ilb
= first_cpu(nohz
.cpu_mask
);
3843 if (ilb
< nr_cpu_ids
)
3849 * If this cpu is idle and doing idle load balancing for all the
3850 * cpus with ticks stopped, is it time for that to stop?
3852 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) == cpu
&&
3853 cpus_weight(nohz
.cpu_mask
) == num_online_cpus()) {
3859 * If this cpu is idle and the idle load balancing is done by
3860 * someone else, then no need raise the SCHED_SOFTIRQ
3862 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) != cpu
&&
3863 cpu_isset(cpu
, nohz
.cpu_mask
))
3866 if (time_after_eq(jiffies
, rq
->next_balance
))
3867 raise_softirq(SCHED_SOFTIRQ
);
3870 #else /* CONFIG_SMP */
3873 * on UP we do not need to balance between CPUs:
3875 static inline void idle_balance(int cpu
, struct rq
*rq
)
3881 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
3883 EXPORT_PER_CPU_SYMBOL(kstat
);
3886 * Return p->sum_exec_runtime plus any more ns on the sched_clock
3887 * that have not yet been banked in case the task is currently running.
3889 unsigned long long task_sched_runtime(struct task_struct
*p
)
3891 unsigned long flags
;
3895 rq
= task_rq_lock(p
, &flags
);
3896 ns
= p
->se
.sum_exec_runtime
;
3897 if (task_current(rq
, p
)) {
3898 update_rq_clock(rq
);
3899 delta_exec
= rq
->clock
- p
->se
.exec_start
;
3900 if ((s64
)delta_exec
> 0)
3903 task_rq_unlock(rq
, &flags
);
3909 * Account user cpu time to a process.
3910 * @p: the process that the cpu time gets accounted to
3911 * @cputime: the cpu time spent in user space since the last update
3913 void account_user_time(struct task_struct
*p
, cputime_t cputime
)
3915 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3918 p
->utime
= cputime_add(p
->utime
, cputime
);
3920 /* Add user time to cpustat. */
3921 tmp
= cputime_to_cputime64(cputime
);
3922 if (TASK_NICE(p
) > 0)
3923 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3925 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3929 * Account guest cpu time to a process.
3930 * @p: the process that the cpu time gets accounted to
3931 * @cputime: the cpu time spent in virtual machine since the last update
3933 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
)
3936 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3938 tmp
= cputime_to_cputime64(cputime
);
3940 p
->utime
= cputime_add(p
->utime
, cputime
);
3941 p
->gtime
= cputime_add(p
->gtime
, cputime
);
3943 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3944 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
3948 * Account scaled user cpu time to a process.
3949 * @p: the process that the cpu time gets accounted to
3950 * @cputime: the cpu time spent in user space since the last update
3952 void account_user_time_scaled(struct task_struct
*p
, cputime_t cputime
)
3954 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime
);
3958 * Account system cpu time to a process.
3959 * @p: the process that the cpu time gets accounted to
3960 * @hardirq_offset: the offset to subtract from hardirq_count()
3961 * @cputime: the cpu time spent in kernel space since the last update
3963 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
3966 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3967 struct rq
*rq
= this_rq();
3970 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
3971 account_guest_time(p
, cputime
);
3975 p
->stime
= cputime_add(p
->stime
, cputime
);
3977 /* Add system time to cpustat. */
3978 tmp
= cputime_to_cputime64(cputime
);
3979 if (hardirq_count() - hardirq_offset
)
3980 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
3981 else if (softirq_count())
3982 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
3983 else if (p
!= rq
->idle
)
3984 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
3985 else if (atomic_read(&rq
->nr_iowait
) > 0)
3986 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, tmp
);
3988 cpustat
->idle
= cputime64_add(cpustat
->idle
, tmp
);
3989 /* Account for system time used */
3990 acct_update_integrals(p
);
3994 * Account scaled system cpu time to a process.
3995 * @p: the process that the cpu time gets accounted to
3996 * @hardirq_offset: the offset to subtract from hardirq_count()
3997 * @cputime: the cpu time spent in kernel space since the last update
3999 void account_system_time_scaled(struct task_struct
*p
, cputime_t cputime
)
4001 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime
);
4005 * Account for involuntary wait time.
4006 * @p: the process from which the cpu time has been stolen
4007 * @steal: the cpu time spent in involuntary wait
4009 void account_steal_time(struct task_struct
*p
, cputime_t steal
)
4011 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4012 cputime64_t tmp
= cputime_to_cputime64(steal
);
4013 struct rq
*rq
= this_rq();
4015 if (p
== rq
->idle
) {
4016 p
->stime
= cputime_add(p
->stime
, steal
);
4017 if (atomic_read(&rq
->nr_iowait
) > 0)
4018 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, tmp
);
4020 cpustat
->idle
= cputime64_add(cpustat
->idle
, tmp
);
4022 cpustat
->steal
= cputime64_add(cpustat
->steal
, tmp
);
4026 * This function gets called by the timer code, with HZ frequency.
4027 * We call it with interrupts disabled.
4029 * It also gets called by the fork code, when changing the parent's
4032 void scheduler_tick(void)
4034 int cpu
= smp_processor_id();
4035 struct rq
*rq
= cpu_rq(cpu
);
4036 struct task_struct
*curr
= rq
->curr
;
4040 spin_lock(&rq
->lock
);
4041 update_rq_clock(rq
);
4042 update_cpu_load(rq
);
4043 curr
->sched_class
->task_tick(rq
, curr
, 0);
4044 spin_unlock(&rq
->lock
);
4047 rq
->idle_at_tick
= idle_cpu(cpu
);
4048 trigger_load_balance(rq
, cpu
);
4052 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
4053 defined(CONFIG_PREEMPT_TRACER))
4055 static inline unsigned long get_parent_ip(unsigned long addr
)
4057 if (in_lock_functions(addr
)) {
4058 addr
= CALLER_ADDR2
;
4059 if (in_lock_functions(addr
))
4060 addr
= CALLER_ADDR3
;
4065 void __kprobes
add_preempt_count(int val
)
4067 #ifdef CONFIG_DEBUG_PREEMPT
4071 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
4074 preempt_count() += val
;
4075 #ifdef CONFIG_DEBUG_PREEMPT
4077 * Spinlock count overflowing soon?
4079 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
4082 if (preempt_count() == val
)
4083 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
4085 EXPORT_SYMBOL(add_preempt_count
);
4087 void __kprobes
sub_preempt_count(int val
)
4089 #ifdef CONFIG_DEBUG_PREEMPT
4093 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
4096 * Is the spinlock portion underflowing?
4098 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
4099 !(preempt_count() & PREEMPT_MASK
)))
4103 if (preempt_count() == val
)
4104 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
4105 preempt_count() -= val
;
4107 EXPORT_SYMBOL(sub_preempt_count
);
4112 * Print scheduling while atomic bug:
4114 static noinline
void __schedule_bug(struct task_struct
*prev
)
4116 struct pt_regs
*regs
= get_irq_regs();
4118 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
4119 prev
->comm
, prev
->pid
, preempt_count());
4121 debug_show_held_locks(prev
);
4122 if (irqs_disabled())
4123 print_irqtrace_events(prev
);
4132 * Various schedule()-time debugging checks and statistics:
4134 static inline void schedule_debug(struct task_struct
*prev
)
4137 * Test if we are atomic. Since do_exit() needs to call into
4138 * schedule() atomically, we ignore that path for now.
4139 * Otherwise, whine if we are scheduling when we should not be.
4141 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
4142 __schedule_bug(prev
);
4144 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
4146 schedstat_inc(this_rq(), sched_count
);
4147 #ifdef CONFIG_SCHEDSTATS
4148 if (unlikely(prev
->lock_depth
>= 0)) {
4149 schedstat_inc(this_rq(), bkl_count
);
4150 schedstat_inc(prev
, sched_info
.bkl_count
);
4156 * Pick up the highest-prio task:
4158 static inline struct task_struct
*
4159 pick_next_task(struct rq
*rq
, struct task_struct
*prev
)
4161 const struct sched_class
*class;
4162 struct task_struct
*p
;
4165 * Optimization: we know that if all tasks are in
4166 * the fair class we can call that function directly:
4168 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
4169 p
= fair_sched_class
.pick_next_task(rq
);
4174 class = sched_class_highest
;
4176 p
= class->pick_next_task(rq
);
4180 * Will never be NULL as the idle class always
4181 * returns a non-NULL p:
4183 class = class->next
;
4188 * schedule() is the main scheduler function.
4190 asmlinkage
void __sched
schedule(void)
4192 struct task_struct
*prev
, *next
;
4193 unsigned long *switch_count
;
4199 cpu
= smp_processor_id();
4203 switch_count
= &prev
->nivcsw
;
4205 release_kernel_lock(prev
);
4206 need_resched_nonpreemptible
:
4208 schedule_debug(prev
);
4213 * Do the rq-clock update outside the rq lock:
4215 local_irq_disable();
4216 update_rq_clock(rq
);
4217 spin_lock(&rq
->lock
);
4218 clear_tsk_need_resched(prev
);
4220 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
4221 if (unlikely(signal_pending_state(prev
->state
, prev
)))
4222 prev
->state
= TASK_RUNNING
;
4224 deactivate_task(rq
, prev
, 1);
4225 switch_count
= &prev
->nvcsw
;
4229 if (prev
->sched_class
->pre_schedule
)
4230 prev
->sched_class
->pre_schedule(rq
, prev
);
4233 if (unlikely(!rq
->nr_running
))
4234 idle_balance(cpu
, rq
);
4236 prev
->sched_class
->put_prev_task(rq
, prev
);
4237 next
= pick_next_task(rq
, prev
);
4239 if (likely(prev
!= next
)) {
4240 sched_info_switch(prev
, next
);
4246 context_switch(rq
, prev
, next
); /* unlocks the rq */
4248 * the context switch might have flipped the stack from under
4249 * us, hence refresh the local variables.
4251 cpu
= smp_processor_id();
4254 spin_unlock_irq(&rq
->lock
);
4258 if (unlikely(reacquire_kernel_lock(current
) < 0))
4259 goto need_resched_nonpreemptible
;
4261 preempt_enable_no_resched();
4262 if (unlikely(test_thread_flag(TIF_NEED_RESCHED
)))
4265 EXPORT_SYMBOL(schedule
);
4267 #ifdef CONFIG_PREEMPT
4269 * this is the entry point to schedule() from in-kernel preemption
4270 * off of preempt_enable. Kernel preemptions off return from interrupt
4271 * occur there and call schedule directly.
4273 asmlinkage
void __sched
preempt_schedule(void)
4275 struct thread_info
*ti
= current_thread_info();
4278 * If there is a non-zero preempt_count or interrupts are disabled,
4279 * we do not want to preempt the current task. Just return..
4281 if (likely(ti
->preempt_count
|| irqs_disabled()))
4285 add_preempt_count(PREEMPT_ACTIVE
);
4287 sub_preempt_count(PREEMPT_ACTIVE
);
4290 * Check again in case we missed a preemption opportunity
4291 * between schedule and now.
4294 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4296 EXPORT_SYMBOL(preempt_schedule
);
4299 * this is the entry point to schedule() from kernel preemption
4300 * off of irq context.
4301 * Note, that this is called and return with irqs disabled. This will
4302 * protect us against recursive calling from irq.
4304 asmlinkage
void __sched
preempt_schedule_irq(void)
4306 struct thread_info
*ti
= current_thread_info();
4308 /* Catch callers which need to be fixed */
4309 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
4312 add_preempt_count(PREEMPT_ACTIVE
);
4315 local_irq_disable();
4316 sub_preempt_count(PREEMPT_ACTIVE
);
4319 * Check again in case we missed a preemption opportunity
4320 * between schedule and now.
4323 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4326 #endif /* CONFIG_PREEMPT */
4328 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int sync
,
4331 return try_to_wake_up(curr
->private, mode
, sync
);
4333 EXPORT_SYMBOL(default_wake_function
);
4336 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4337 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
4338 * number) then we wake all the non-exclusive tasks and one exclusive task.
4340 * There are circumstances in which we can try to wake a task which has already
4341 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
4342 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4344 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
4345 int nr_exclusive
, int sync
, void *key
)
4347 wait_queue_t
*curr
, *next
;
4349 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
4350 unsigned flags
= curr
->flags
;
4352 if (curr
->func(curr
, mode
, sync
, key
) &&
4353 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
4359 * __wake_up - wake up threads blocked on a waitqueue.
4361 * @mode: which threads
4362 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4363 * @key: is directly passed to the wakeup function
4365 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
4366 int nr_exclusive
, void *key
)
4368 unsigned long flags
;
4370 spin_lock_irqsave(&q
->lock
, flags
);
4371 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
4372 spin_unlock_irqrestore(&q
->lock
, flags
);
4374 EXPORT_SYMBOL(__wake_up
);
4377 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4379 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
4381 __wake_up_common(q
, mode
, 1, 0, NULL
);
4385 * __wake_up_sync - wake up threads blocked on a waitqueue.
4387 * @mode: which threads
4388 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4390 * The sync wakeup differs that the waker knows that it will schedule
4391 * away soon, so while the target thread will be woken up, it will not
4392 * be migrated to another CPU - ie. the two threads are 'synchronized'
4393 * with each other. This can prevent needless bouncing between CPUs.
4395 * On UP it can prevent extra preemption.
4398 __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
4400 unsigned long flags
;
4406 if (unlikely(!nr_exclusive
))
4409 spin_lock_irqsave(&q
->lock
, flags
);
4410 __wake_up_common(q
, mode
, nr_exclusive
, sync
, NULL
);
4411 spin_unlock_irqrestore(&q
->lock
, flags
);
4413 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
4415 void complete(struct completion
*x
)
4417 unsigned long flags
;
4419 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4421 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
4422 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4424 EXPORT_SYMBOL(complete
);
4426 void complete_all(struct completion
*x
)
4428 unsigned long flags
;
4430 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4431 x
->done
+= UINT_MAX
/2;
4432 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
4433 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4435 EXPORT_SYMBOL(complete_all
);
4437 static inline long __sched
4438 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
4441 DECLARE_WAITQUEUE(wait
, current
);
4443 wait
.flags
|= WQ_FLAG_EXCLUSIVE
;
4444 __add_wait_queue_tail(&x
->wait
, &wait
);
4446 if ((state
== TASK_INTERRUPTIBLE
&&
4447 signal_pending(current
)) ||
4448 (state
== TASK_KILLABLE
&&
4449 fatal_signal_pending(current
))) {
4450 __remove_wait_queue(&x
->wait
, &wait
);
4451 return -ERESTARTSYS
;
4453 __set_current_state(state
);
4454 spin_unlock_irq(&x
->wait
.lock
);
4455 timeout
= schedule_timeout(timeout
);
4456 spin_lock_irq(&x
->wait
.lock
);
4458 __remove_wait_queue(&x
->wait
, &wait
);
4462 __remove_wait_queue(&x
->wait
, &wait
);
4469 wait_for_common(struct completion
*x
, long timeout
, int state
)
4473 spin_lock_irq(&x
->wait
.lock
);
4474 timeout
= do_wait_for_common(x
, timeout
, state
);
4475 spin_unlock_irq(&x
->wait
.lock
);
4479 void __sched
wait_for_completion(struct completion
*x
)
4481 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
4483 EXPORT_SYMBOL(wait_for_completion
);
4485 unsigned long __sched
4486 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
4488 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
4490 EXPORT_SYMBOL(wait_for_completion_timeout
);
4492 int __sched
wait_for_completion_interruptible(struct completion
*x
)
4494 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
4495 if (t
== -ERESTARTSYS
)
4499 EXPORT_SYMBOL(wait_for_completion_interruptible
);
4501 unsigned long __sched
4502 wait_for_completion_interruptible_timeout(struct completion
*x
,
4503 unsigned long timeout
)
4505 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
4507 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
4509 int __sched
wait_for_completion_killable(struct completion
*x
)
4511 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
4512 if (t
== -ERESTARTSYS
)
4516 EXPORT_SYMBOL(wait_for_completion_killable
);
4519 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
4521 unsigned long flags
;
4524 init_waitqueue_entry(&wait
, current
);
4526 __set_current_state(state
);
4528 spin_lock_irqsave(&q
->lock
, flags
);
4529 __add_wait_queue(q
, &wait
);
4530 spin_unlock(&q
->lock
);
4531 timeout
= schedule_timeout(timeout
);
4532 spin_lock_irq(&q
->lock
);
4533 __remove_wait_queue(q
, &wait
);
4534 spin_unlock_irqrestore(&q
->lock
, flags
);
4539 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
4541 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4543 EXPORT_SYMBOL(interruptible_sleep_on
);
4546 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4548 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
4550 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
4552 void __sched
sleep_on(wait_queue_head_t
*q
)
4554 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4556 EXPORT_SYMBOL(sleep_on
);
4558 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4560 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
4562 EXPORT_SYMBOL(sleep_on_timeout
);
4564 #ifdef CONFIG_RT_MUTEXES
4567 * rt_mutex_setprio - set the current priority of a task
4569 * @prio: prio value (kernel-internal form)
4571 * This function changes the 'effective' priority of a task. It does
4572 * not touch ->normal_prio like __setscheduler().
4574 * Used by the rt_mutex code to implement priority inheritance logic.
4576 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
4578 unsigned long flags
;
4579 int oldprio
, on_rq
, running
;
4581 const struct sched_class
*prev_class
= p
->sched_class
;
4583 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
4585 rq
= task_rq_lock(p
, &flags
);
4586 update_rq_clock(rq
);
4589 on_rq
= p
->se
.on_rq
;
4590 running
= task_current(rq
, p
);
4592 dequeue_task(rq
, p
, 0);
4594 p
->sched_class
->put_prev_task(rq
, p
);
4597 p
->sched_class
= &rt_sched_class
;
4599 p
->sched_class
= &fair_sched_class
;
4604 p
->sched_class
->set_curr_task(rq
);
4606 enqueue_task(rq
, p
, 0);
4608 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4610 task_rq_unlock(rq
, &flags
);
4615 void set_user_nice(struct task_struct
*p
, long nice
)
4617 int old_prio
, delta
, on_rq
;
4618 unsigned long flags
;
4621 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
4624 * We have to be careful, if called from sys_setpriority(),
4625 * the task might be in the middle of scheduling on another CPU.
4627 rq
= task_rq_lock(p
, &flags
);
4628 update_rq_clock(rq
);
4630 * The RT priorities are set via sched_setscheduler(), but we still
4631 * allow the 'normal' nice value to be set - but as expected
4632 * it wont have any effect on scheduling until the task is
4633 * SCHED_FIFO/SCHED_RR:
4635 if (task_has_rt_policy(p
)) {
4636 p
->static_prio
= NICE_TO_PRIO(nice
);
4639 on_rq
= p
->se
.on_rq
;
4641 dequeue_task(rq
, p
, 0);
4645 p
->static_prio
= NICE_TO_PRIO(nice
);
4648 p
->prio
= effective_prio(p
);
4649 delta
= p
->prio
- old_prio
;
4652 enqueue_task(rq
, p
, 0);
4655 * If the task increased its priority or is running and
4656 * lowered its priority, then reschedule its CPU:
4658 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
4659 resched_task(rq
->curr
);
4662 task_rq_unlock(rq
, &flags
);
4664 EXPORT_SYMBOL(set_user_nice
);
4667 * can_nice - check if a task can reduce its nice value
4671 int can_nice(const struct task_struct
*p
, const int nice
)
4673 /* convert nice value [19,-20] to rlimit style value [1,40] */
4674 int nice_rlim
= 20 - nice
;
4676 return (nice_rlim
<= p
->signal
->rlim
[RLIMIT_NICE
].rlim_cur
||
4677 capable(CAP_SYS_NICE
));
4680 #ifdef __ARCH_WANT_SYS_NICE
4683 * sys_nice - change the priority of the current process.
4684 * @increment: priority increment
4686 * sys_setpriority is a more generic, but much slower function that
4687 * does similar things.
4689 asmlinkage
long sys_nice(int increment
)
4694 * Setpriority might change our priority at the same moment.
4695 * We don't have to worry. Conceptually one call occurs first
4696 * and we have a single winner.
4698 if (increment
< -40)
4703 nice
= PRIO_TO_NICE(current
->static_prio
) + increment
;
4709 if (increment
< 0 && !can_nice(current
, nice
))
4712 retval
= security_task_setnice(current
, nice
);
4716 set_user_nice(current
, nice
);
4723 * task_prio - return the priority value of a given task.
4724 * @p: the task in question.
4726 * This is the priority value as seen by users in /proc.
4727 * RT tasks are offset by -200. Normal tasks are centered
4728 * around 0, value goes from -16 to +15.
4730 int task_prio(const struct task_struct
*p
)
4732 return p
->prio
- MAX_RT_PRIO
;
4736 * task_nice - return the nice value of a given task.
4737 * @p: the task in question.
4739 int task_nice(const struct task_struct
*p
)
4741 return TASK_NICE(p
);
4743 EXPORT_SYMBOL(task_nice
);
4746 * idle_cpu - is a given cpu idle currently?
4747 * @cpu: the processor in question.
4749 int idle_cpu(int cpu
)
4751 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
4755 * idle_task - return the idle task for a given cpu.
4756 * @cpu: the processor in question.
4758 struct task_struct
*idle_task(int cpu
)
4760 return cpu_rq(cpu
)->idle
;
4764 * find_process_by_pid - find a process with a matching PID value.
4765 * @pid: the pid in question.
4767 static struct task_struct
*find_process_by_pid(pid_t pid
)
4769 return pid
? find_task_by_vpid(pid
) : current
;
4772 /* Actually do priority change: must hold rq lock. */
4774 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
4776 BUG_ON(p
->se
.on_rq
);
4779 switch (p
->policy
) {
4783 p
->sched_class
= &fair_sched_class
;
4787 p
->sched_class
= &rt_sched_class
;
4791 p
->rt_priority
= prio
;
4792 p
->normal_prio
= normal_prio(p
);
4793 /* we are holding p->pi_lock already */
4794 p
->prio
= rt_mutex_getprio(p
);
4799 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
4800 * @p: the task in question.
4801 * @policy: new policy.
4802 * @param: structure containing the new RT priority.
4804 * NOTE that the task may be already dead.
4806 int sched_setscheduler(struct task_struct
*p
, int policy
,
4807 struct sched_param
*param
)
4809 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
4810 unsigned long flags
;
4811 const struct sched_class
*prev_class
= p
->sched_class
;
4814 /* may grab non-irq protected spin_locks */
4815 BUG_ON(in_interrupt());
4817 /* double check policy once rq lock held */
4819 policy
= oldpolicy
= p
->policy
;
4820 else if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
4821 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
4822 policy
!= SCHED_IDLE
)
4825 * Valid priorities for SCHED_FIFO and SCHED_RR are
4826 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4827 * SCHED_BATCH and SCHED_IDLE is 0.
4829 if (param
->sched_priority
< 0 ||
4830 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
4831 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
4833 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
4837 * Allow unprivileged RT tasks to decrease priority:
4839 if (!capable(CAP_SYS_NICE
)) {
4840 if (rt_policy(policy
)) {
4841 unsigned long rlim_rtprio
;
4843 if (!lock_task_sighand(p
, &flags
))
4845 rlim_rtprio
= p
->signal
->rlim
[RLIMIT_RTPRIO
].rlim_cur
;
4846 unlock_task_sighand(p
, &flags
);
4848 /* can't set/change the rt policy */
4849 if (policy
!= p
->policy
&& !rlim_rtprio
)
4852 /* can't increase priority */
4853 if (param
->sched_priority
> p
->rt_priority
&&
4854 param
->sched_priority
> rlim_rtprio
)
4858 * Like positive nice levels, dont allow tasks to
4859 * move out of SCHED_IDLE either:
4861 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
4864 /* can't change other user's priorities */
4865 if ((current
->euid
!= p
->euid
) &&
4866 (current
->euid
!= p
->uid
))
4870 #ifdef CONFIG_RT_GROUP_SCHED
4872 * Do not allow realtime tasks into groups that have no runtime
4875 if (rt_policy(policy
) && task_group(p
)->rt_bandwidth
.rt_runtime
== 0)
4879 retval
= security_task_setscheduler(p
, policy
, param
);
4883 * make sure no PI-waiters arrive (or leave) while we are
4884 * changing the priority of the task:
4886 spin_lock_irqsave(&p
->pi_lock
, flags
);
4888 * To be able to change p->policy safely, the apropriate
4889 * runqueue lock must be held.
4891 rq
= __task_rq_lock(p
);
4892 /* recheck policy now with rq lock held */
4893 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
4894 policy
= oldpolicy
= -1;
4895 __task_rq_unlock(rq
);
4896 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4899 update_rq_clock(rq
);
4900 on_rq
= p
->se
.on_rq
;
4901 running
= task_current(rq
, p
);
4903 deactivate_task(rq
, p
, 0);
4905 p
->sched_class
->put_prev_task(rq
, p
);
4908 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
4911 p
->sched_class
->set_curr_task(rq
);
4913 activate_task(rq
, p
, 0);
4915 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4917 __task_rq_unlock(rq
);
4918 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4920 rt_mutex_adjust_pi(p
);
4924 EXPORT_SYMBOL_GPL(sched_setscheduler
);
4927 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4929 struct sched_param lparam
;
4930 struct task_struct
*p
;
4933 if (!param
|| pid
< 0)
4935 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
4940 p
= find_process_by_pid(pid
);
4942 retval
= sched_setscheduler(p
, policy
, &lparam
);
4949 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4950 * @pid: the pid in question.
4951 * @policy: new policy.
4952 * @param: structure containing the new RT priority.
4955 sys_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4957 /* negative values for policy are not valid */
4961 return do_sched_setscheduler(pid
, policy
, param
);
4965 * sys_sched_setparam - set/change the RT priority of a thread
4966 * @pid: the pid in question.
4967 * @param: structure containing the new RT priority.
4969 asmlinkage
long sys_sched_setparam(pid_t pid
, struct sched_param __user
*param
)
4971 return do_sched_setscheduler(pid
, -1, param
);
4975 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4976 * @pid: the pid in question.
4978 asmlinkage
long sys_sched_getscheduler(pid_t pid
)
4980 struct task_struct
*p
;
4987 read_lock(&tasklist_lock
);
4988 p
= find_process_by_pid(pid
);
4990 retval
= security_task_getscheduler(p
);
4994 read_unlock(&tasklist_lock
);
4999 * sys_sched_getscheduler - get the RT priority of a thread
5000 * @pid: the pid in question.
5001 * @param: structure containing the RT priority.
5003 asmlinkage
long sys_sched_getparam(pid_t pid
, struct sched_param __user
*param
)
5005 struct sched_param lp
;
5006 struct task_struct
*p
;
5009 if (!param
|| pid
< 0)
5012 read_lock(&tasklist_lock
);
5013 p
= find_process_by_pid(pid
);
5018 retval
= security_task_getscheduler(p
);
5022 lp
.sched_priority
= p
->rt_priority
;
5023 read_unlock(&tasklist_lock
);
5026 * This one might sleep, we cannot do it with a spinlock held ...
5028 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
5033 read_unlock(&tasklist_lock
);
5037 long sched_setaffinity(pid_t pid
, const cpumask_t
*in_mask
)
5039 cpumask_t cpus_allowed
;
5040 cpumask_t new_mask
= *in_mask
;
5041 struct task_struct
*p
;
5045 read_lock(&tasklist_lock
);
5047 p
= find_process_by_pid(pid
);
5049 read_unlock(&tasklist_lock
);
5055 * It is not safe to call set_cpus_allowed with the
5056 * tasklist_lock held. We will bump the task_struct's
5057 * usage count and then drop tasklist_lock.
5060 read_unlock(&tasklist_lock
);
5063 if ((current
->euid
!= p
->euid
) && (current
->euid
!= p
->uid
) &&
5064 !capable(CAP_SYS_NICE
))
5067 retval
= security_task_setscheduler(p
, 0, NULL
);
5071 cpuset_cpus_allowed(p
, &cpus_allowed
);
5072 cpus_and(new_mask
, new_mask
, cpus_allowed
);
5074 retval
= set_cpus_allowed_ptr(p
, &new_mask
);
5077 cpuset_cpus_allowed(p
, &cpus_allowed
);
5078 if (!cpus_subset(new_mask
, cpus_allowed
)) {
5080 * We must have raced with a concurrent cpuset
5081 * update. Just reset the cpus_allowed to the
5082 * cpuset's cpus_allowed
5084 new_mask
= cpus_allowed
;
5094 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
5095 cpumask_t
*new_mask
)
5097 if (len
< sizeof(cpumask_t
)) {
5098 memset(new_mask
, 0, sizeof(cpumask_t
));
5099 } else if (len
> sizeof(cpumask_t
)) {
5100 len
= sizeof(cpumask_t
);
5102 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
5106 * sys_sched_setaffinity - set the cpu affinity of a process
5107 * @pid: pid of the process
5108 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5109 * @user_mask_ptr: user-space pointer to the new cpu mask
5111 asmlinkage
long sys_sched_setaffinity(pid_t pid
, unsigned int len
,
5112 unsigned long __user
*user_mask_ptr
)
5117 retval
= get_user_cpu_mask(user_mask_ptr
, len
, &new_mask
);
5121 return sched_setaffinity(pid
, &new_mask
);
5125 * Represents all cpu's present in the system
5126 * In systems capable of hotplug, this map could dynamically grow
5127 * as new cpu's are detected in the system via any platform specific
5128 * method, such as ACPI for e.g.
5131 cpumask_t cpu_present_map __read_mostly
;
5132 EXPORT_SYMBOL(cpu_present_map
);
5135 cpumask_t cpu_online_map __read_mostly
= CPU_MASK_ALL
;
5136 EXPORT_SYMBOL(cpu_online_map
);
5138 cpumask_t cpu_possible_map __read_mostly
= CPU_MASK_ALL
;
5139 EXPORT_SYMBOL(cpu_possible_map
);
5142 long sched_getaffinity(pid_t pid
, cpumask_t
*mask
)
5144 struct task_struct
*p
;
5148 read_lock(&tasklist_lock
);
5151 p
= find_process_by_pid(pid
);
5155 retval
= security_task_getscheduler(p
);
5159 cpus_and(*mask
, p
->cpus_allowed
, cpu_online_map
);
5162 read_unlock(&tasklist_lock
);
5169 * sys_sched_getaffinity - get the cpu affinity of a process
5170 * @pid: pid of the process
5171 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5172 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5174 asmlinkage
long sys_sched_getaffinity(pid_t pid
, unsigned int len
,
5175 unsigned long __user
*user_mask_ptr
)
5180 if (len
< sizeof(cpumask_t
))
5183 ret
= sched_getaffinity(pid
, &mask
);
5187 if (copy_to_user(user_mask_ptr
, &mask
, sizeof(cpumask_t
)))
5190 return sizeof(cpumask_t
);
5194 * sys_sched_yield - yield the current processor to other threads.
5196 * This function yields the current CPU to other tasks. If there are no
5197 * other threads running on this CPU then this function will return.
5199 asmlinkage
long sys_sched_yield(void)
5201 struct rq
*rq
= this_rq_lock();
5203 schedstat_inc(rq
, yld_count
);
5204 current
->sched_class
->yield_task(rq
);
5207 * Since we are going to call schedule() anyway, there's
5208 * no need to preempt or enable interrupts:
5210 __release(rq
->lock
);
5211 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
5212 _raw_spin_unlock(&rq
->lock
);
5213 preempt_enable_no_resched();
5220 static void __cond_resched(void)
5222 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
5223 __might_sleep(__FILE__
, __LINE__
);
5226 * The BKS might be reacquired before we have dropped
5227 * PREEMPT_ACTIVE, which could trigger a second
5228 * cond_resched() call.
5231 add_preempt_count(PREEMPT_ACTIVE
);
5233 sub_preempt_count(PREEMPT_ACTIVE
);
5234 } while (need_resched());
5237 int __sched
_cond_resched(void)
5239 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE
) &&
5240 system_state
== SYSTEM_RUNNING
) {
5246 EXPORT_SYMBOL(_cond_resched
);
5249 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
5250 * call schedule, and on return reacquire the lock.
5252 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5253 * operations here to prevent schedule() from being called twice (once via
5254 * spin_unlock(), once by hand).
5256 int cond_resched_lock(spinlock_t
*lock
)
5258 int resched
= need_resched() && system_state
== SYSTEM_RUNNING
;
5261 if (spin_needbreak(lock
) || resched
) {
5263 if (resched
&& need_resched())
5272 EXPORT_SYMBOL(cond_resched_lock
);
5274 int __sched
cond_resched_softirq(void)
5276 BUG_ON(!in_softirq());
5278 if (need_resched() && system_state
== SYSTEM_RUNNING
) {
5286 EXPORT_SYMBOL(cond_resched_softirq
);
5289 * yield - yield the current processor to other threads.
5291 * This is a shortcut for kernel-space yielding - it marks the
5292 * thread runnable and calls sys_sched_yield().
5294 void __sched
yield(void)
5296 set_current_state(TASK_RUNNING
);
5299 EXPORT_SYMBOL(yield
);
5302 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5303 * that process accounting knows that this is a task in IO wait state.
5305 * But don't do that if it is a deliberate, throttling IO wait (this task
5306 * has set its backing_dev_info: the queue against which it should throttle)
5308 void __sched
io_schedule(void)
5310 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5312 delayacct_blkio_start();
5313 atomic_inc(&rq
->nr_iowait
);
5315 atomic_dec(&rq
->nr_iowait
);
5316 delayacct_blkio_end();
5318 EXPORT_SYMBOL(io_schedule
);
5320 long __sched
io_schedule_timeout(long timeout
)
5322 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5325 delayacct_blkio_start();
5326 atomic_inc(&rq
->nr_iowait
);
5327 ret
= schedule_timeout(timeout
);
5328 atomic_dec(&rq
->nr_iowait
);
5329 delayacct_blkio_end();
5334 * sys_sched_get_priority_max - return maximum RT priority.
5335 * @policy: scheduling class.
5337 * this syscall returns the maximum rt_priority that can be used
5338 * by a given scheduling class.
5340 asmlinkage
long sys_sched_get_priority_max(int policy
)
5347 ret
= MAX_USER_RT_PRIO
-1;
5359 * sys_sched_get_priority_min - return minimum RT priority.
5360 * @policy: scheduling class.
5362 * this syscall returns the minimum rt_priority that can be used
5363 * by a given scheduling class.
5365 asmlinkage
long sys_sched_get_priority_min(int policy
)
5383 * sys_sched_rr_get_interval - return the default timeslice of a process.
5384 * @pid: pid of the process.
5385 * @interval: userspace pointer to the timeslice value.
5387 * this syscall writes the default timeslice value of a given process
5388 * into the user-space timespec buffer. A value of '0' means infinity.
5391 long sys_sched_rr_get_interval(pid_t pid
, struct timespec __user
*interval
)
5393 struct task_struct
*p
;
5394 unsigned int time_slice
;
5402 read_lock(&tasklist_lock
);
5403 p
= find_process_by_pid(pid
);
5407 retval
= security_task_getscheduler(p
);
5412 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
5413 * tasks that are on an otherwise idle runqueue:
5416 if (p
->policy
== SCHED_RR
) {
5417 time_slice
= DEF_TIMESLICE
;
5418 } else if (p
->policy
!= SCHED_FIFO
) {
5419 struct sched_entity
*se
= &p
->se
;
5420 unsigned long flags
;
5423 rq
= task_rq_lock(p
, &flags
);
5424 if (rq
->cfs
.load
.weight
)
5425 time_slice
= NS_TO_JIFFIES(sched_slice(&rq
->cfs
, se
));
5426 task_rq_unlock(rq
, &flags
);
5428 read_unlock(&tasklist_lock
);
5429 jiffies_to_timespec(time_slice
, &t
);
5430 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
5434 read_unlock(&tasklist_lock
);
5438 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
5440 void sched_show_task(struct task_struct
*p
)
5442 unsigned long free
= 0;
5445 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
5446 printk(KERN_INFO
"%-13.13s %c", p
->comm
,
5447 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
5448 #if BITS_PER_LONG == 32
5449 if (state
== TASK_RUNNING
)
5450 printk(KERN_CONT
" running ");
5452 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
5454 if (state
== TASK_RUNNING
)
5455 printk(KERN_CONT
" running task ");
5457 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
5459 #ifdef CONFIG_DEBUG_STACK_USAGE
5461 unsigned long *n
= end_of_stack(p
);
5464 free
= (unsigned long)n
- (unsigned long)end_of_stack(p
);
5467 printk(KERN_CONT
"%5lu %5d %6d\n", free
,
5468 task_pid_nr(p
), task_pid_nr(p
->real_parent
));
5470 show_stack(p
, NULL
);
5473 void show_state_filter(unsigned long state_filter
)
5475 struct task_struct
*g
, *p
;
5477 #if BITS_PER_LONG == 32
5479 " task PC stack pid father\n");
5482 " task PC stack pid father\n");
5484 read_lock(&tasklist_lock
);
5485 do_each_thread(g
, p
) {
5487 * reset the NMI-timeout, listing all files on a slow
5488 * console might take alot of time:
5490 touch_nmi_watchdog();
5491 if (!state_filter
|| (p
->state
& state_filter
))
5493 } while_each_thread(g
, p
);
5495 touch_all_softlockup_watchdogs();
5497 #ifdef CONFIG_SCHED_DEBUG
5498 sysrq_sched_debug_show();
5500 read_unlock(&tasklist_lock
);
5502 * Only show locks if all tasks are dumped:
5504 if (state_filter
== -1)
5505 debug_show_all_locks();
5508 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
5510 idle
->sched_class
= &idle_sched_class
;
5514 * init_idle - set up an idle thread for a given CPU
5515 * @idle: task in question
5516 * @cpu: cpu the idle task belongs to
5518 * NOTE: this function does not set the idle thread's NEED_RESCHED
5519 * flag, to make booting more robust.
5521 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
5523 struct rq
*rq
= cpu_rq(cpu
);
5524 unsigned long flags
;
5527 idle
->se
.exec_start
= sched_clock();
5529 idle
->prio
= idle
->normal_prio
= MAX_PRIO
;
5530 idle
->cpus_allowed
= cpumask_of_cpu(cpu
);
5531 __set_task_cpu(idle
, cpu
);
5533 spin_lock_irqsave(&rq
->lock
, flags
);
5534 rq
->curr
= rq
->idle
= idle
;
5535 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
5538 spin_unlock_irqrestore(&rq
->lock
, flags
);
5540 /* Set the preempt count _outside_ the spinlocks! */
5541 #if defined(CONFIG_PREEMPT)
5542 task_thread_info(idle
)->preempt_count
= (idle
->lock_depth
>= 0);
5544 task_thread_info(idle
)->preempt_count
= 0;
5547 * The idle tasks have their own, simple scheduling class:
5549 idle
->sched_class
= &idle_sched_class
;
5553 * In a system that switches off the HZ timer nohz_cpu_mask
5554 * indicates which cpus entered this state. This is used
5555 * in the rcu update to wait only for active cpus. For system
5556 * which do not switch off the HZ timer nohz_cpu_mask should
5557 * always be CPU_MASK_NONE.
5559 cpumask_t nohz_cpu_mask
= CPU_MASK_NONE
;
5562 * Increase the granularity value when there are more CPUs,
5563 * because with more CPUs the 'effective latency' as visible
5564 * to users decreases. But the relationship is not linear,
5565 * so pick a second-best guess by going with the log2 of the
5568 * This idea comes from the SD scheduler of Con Kolivas:
5570 static inline void sched_init_granularity(void)
5572 unsigned int factor
= 1 + ilog2(num_online_cpus());
5573 const unsigned long limit
= 200000000;
5575 sysctl_sched_min_granularity
*= factor
;
5576 if (sysctl_sched_min_granularity
> limit
)
5577 sysctl_sched_min_granularity
= limit
;
5579 sysctl_sched_latency
*= factor
;
5580 if (sysctl_sched_latency
> limit
)
5581 sysctl_sched_latency
= limit
;
5583 sysctl_sched_wakeup_granularity
*= factor
;
5588 * This is how migration works:
5590 * 1) we queue a struct migration_req structure in the source CPU's
5591 * runqueue and wake up that CPU's migration thread.
5592 * 2) we down() the locked semaphore => thread blocks.
5593 * 3) migration thread wakes up (implicitly it forces the migrated
5594 * thread off the CPU)
5595 * 4) it gets the migration request and checks whether the migrated
5596 * task is still in the wrong runqueue.
5597 * 5) if it's in the wrong runqueue then the migration thread removes
5598 * it and puts it into the right queue.
5599 * 6) migration thread up()s the semaphore.
5600 * 7) we wake up and the migration is done.
5604 * Change a given task's CPU affinity. Migrate the thread to a
5605 * proper CPU and schedule it away if the CPU it's executing on
5606 * is removed from the allowed bitmask.
5608 * NOTE: the caller must have a valid reference to the task, the
5609 * task must not exit() & deallocate itself prematurely. The
5610 * call is not atomic; no spinlocks may be held.
5612 int set_cpus_allowed_ptr(struct task_struct
*p
, const cpumask_t
*new_mask
)
5614 struct migration_req req
;
5615 unsigned long flags
;
5619 rq
= task_rq_lock(p
, &flags
);
5620 if (!cpus_intersects(*new_mask
, cpu_online_map
)) {
5625 if (p
->sched_class
->set_cpus_allowed
)
5626 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
5628 p
->cpus_allowed
= *new_mask
;
5629 p
->rt
.nr_cpus_allowed
= cpus_weight(*new_mask
);
5632 /* Can the task run on the task's current CPU? If so, we're done */
5633 if (cpu_isset(task_cpu(p
), *new_mask
))
5636 if (migrate_task(p
, any_online_cpu(*new_mask
), &req
)) {
5637 /* Need help from migration thread: drop lock and wait. */
5638 task_rq_unlock(rq
, &flags
);
5639 wake_up_process(rq
->migration_thread
);
5640 wait_for_completion(&req
.done
);
5641 tlb_migrate_finish(p
->mm
);
5645 task_rq_unlock(rq
, &flags
);
5649 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
5652 * Move (not current) task off this cpu, onto dest cpu. We're doing
5653 * this because either it can't run here any more (set_cpus_allowed()
5654 * away from this CPU, or CPU going down), or because we're
5655 * attempting to rebalance this task on exec (sched_exec).
5657 * So we race with normal scheduler movements, but that's OK, as long
5658 * as the task is no longer on this CPU.
5660 * Returns non-zero if task was successfully migrated.
5662 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5664 struct rq
*rq_dest
, *rq_src
;
5667 if (unlikely(cpu_is_offline(dest_cpu
)))
5670 rq_src
= cpu_rq(src_cpu
);
5671 rq_dest
= cpu_rq(dest_cpu
);
5673 double_rq_lock(rq_src
, rq_dest
);
5674 /* Already moved. */
5675 if (task_cpu(p
) != src_cpu
)
5677 /* Affinity changed (again). */
5678 if (!cpu_isset(dest_cpu
, p
->cpus_allowed
))
5681 on_rq
= p
->se
.on_rq
;
5683 deactivate_task(rq_src
, p
, 0);
5685 set_task_cpu(p
, dest_cpu
);
5687 activate_task(rq_dest
, p
, 0);
5688 check_preempt_curr(rq_dest
, p
);
5692 double_rq_unlock(rq_src
, rq_dest
);
5697 * migration_thread - this is a highprio system thread that performs
5698 * thread migration by bumping thread off CPU then 'pushing' onto
5701 static int migration_thread(void *data
)
5703 int cpu
= (long)data
;
5707 BUG_ON(rq
->migration_thread
!= current
);
5709 set_current_state(TASK_INTERRUPTIBLE
);
5710 while (!kthread_should_stop()) {
5711 struct migration_req
*req
;
5712 struct list_head
*head
;
5714 spin_lock_irq(&rq
->lock
);
5716 if (cpu_is_offline(cpu
)) {
5717 spin_unlock_irq(&rq
->lock
);
5721 if (rq
->active_balance
) {
5722 active_load_balance(rq
, cpu
);
5723 rq
->active_balance
= 0;
5726 head
= &rq
->migration_queue
;
5728 if (list_empty(head
)) {
5729 spin_unlock_irq(&rq
->lock
);
5731 set_current_state(TASK_INTERRUPTIBLE
);
5734 req
= list_entry(head
->next
, struct migration_req
, list
);
5735 list_del_init(head
->next
);
5737 spin_unlock(&rq
->lock
);
5738 __migrate_task(req
->task
, cpu
, req
->dest_cpu
);
5741 complete(&req
->done
);
5743 __set_current_state(TASK_RUNNING
);
5747 /* Wait for kthread_stop */
5748 set_current_state(TASK_INTERRUPTIBLE
);
5749 while (!kthread_should_stop()) {
5751 set_current_state(TASK_INTERRUPTIBLE
);
5753 __set_current_state(TASK_RUNNING
);
5757 #ifdef CONFIG_HOTPLUG_CPU
5759 static int __migrate_task_irq(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5763 local_irq_disable();
5764 ret
= __migrate_task(p
, src_cpu
, dest_cpu
);
5770 * Figure out where task on dead CPU should go, use force if necessary.
5771 * NOTE: interrupts should be disabled by the caller
5773 static void move_task_off_dead_cpu(int dead_cpu
, struct task_struct
*p
)
5775 unsigned long flags
;
5782 mask
= node_to_cpumask(cpu_to_node(dead_cpu
));
5783 cpus_and(mask
, mask
, p
->cpus_allowed
);
5784 dest_cpu
= any_online_cpu(mask
);
5786 /* On any allowed CPU? */
5787 if (dest_cpu
>= nr_cpu_ids
)
5788 dest_cpu
= any_online_cpu(p
->cpus_allowed
);
5790 /* No more Mr. Nice Guy. */
5791 if (dest_cpu
>= nr_cpu_ids
) {
5792 cpumask_t cpus_allowed
;
5794 cpuset_cpus_allowed_locked(p
, &cpus_allowed
);
5796 * Try to stay on the same cpuset, where the
5797 * current cpuset may be a subset of all cpus.
5798 * The cpuset_cpus_allowed_locked() variant of
5799 * cpuset_cpus_allowed() will not block. It must be
5800 * called within calls to cpuset_lock/cpuset_unlock.
5802 rq
= task_rq_lock(p
, &flags
);
5803 p
->cpus_allowed
= cpus_allowed
;
5804 dest_cpu
= any_online_cpu(p
->cpus_allowed
);
5805 task_rq_unlock(rq
, &flags
);
5808 * Don't tell them about moving exiting tasks or
5809 * kernel threads (both mm NULL), since they never
5812 if (p
->mm
&& printk_ratelimit()) {
5813 printk(KERN_INFO
"process %d (%s) no "
5814 "longer affine to cpu%d\n",
5815 task_pid_nr(p
), p
->comm
, dead_cpu
);
5818 } while (!__migrate_task_irq(p
, dead_cpu
, dest_cpu
));
5822 * While a dead CPU has no uninterruptible tasks queued at this point,
5823 * it might still have a nonzero ->nr_uninterruptible counter, because
5824 * for performance reasons the counter is not stricly tracking tasks to
5825 * their home CPUs. So we just add the counter to another CPU's counter,
5826 * to keep the global sum constant after CPU-down:
5828 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
5830 struct rq
*rq_dest
= cpu_rq(any_online_cpu(*CPU_MASK_ALL_PTR
));
5831 unsigned long flags
;
5833 local_irq_save(flags
);
5834 double_rq_lock(rq_src
, rq_dest
);
5835 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
5836 rq_src
->nr_uninterruptible
= 0;
5837 double_rq_unlock(rq_src
, rq_dest
);
5838 local_irq_restore(flags
);
5841 /* Run through task list and migrate tasks from the dead cpu. */
5842 static void migrate_live_tasks(int src_cpu
)
5844 struct task_struct
*p
, *t
;
5846 read_lock(&tasklist_lock
);
5848 do_each_thread(t
, p
) {
5852 if (task_cpu(p
) == src_cpu
)
5853 move_task_off_dead_cpu(src_cpu
, p
);
5854 } while_each_thread(t
, p
);
5856 read_unlock(&tasklist_lock
);
5860 * Schedules idle task to be the next runnable task on current CPU.
5861 * It does so by boosting its priority to highest possible.
5862 * Used by CPU offline code.
5864 void sched_idle_next(void)
5866 int this_cpu
= smp_processor_id();
5867 struct rq
*rq
= cpu_rq(this_cpu
);
5868 struct task_struct
*p
= rq
->idle
;
5869 unsigned long flags
;
5871 /* cpu has to be offline */
5872 BUG_ON(cpu_online(this_cpu
));
5875 * Strictly not necessary since rest of the CPUs are stopped by now
5876 * and interrupts disabled on the current cpu.
5878 spin_lock_irqsave(&rq
->lock
, flags
);
5880 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
5882 update_rq_clock(rq
);
5883 activate_task(rq
, p
, 0);
5885 spin_unlock_irqrestore(&rq
->lock
, flags
);
5889 * Ensures that the idle task is using init_mm right before its cpu goes
5892 void idle_task_exit(void)
5894 struct mm_struct
*mm
= current
->active_mm
;
5896 BUG_ON(cpu_online(smp_processor_id()));
5899 switch_mm(mm
, &init_mm
, current
);
5903 /* called under rq->lock with disabled interrupts */
5904 static void migrate_dead(unsigned int dead_cpu
, struct task_struct
*p
)
5906 struct rq
*rq
= cpu_rq(dead_cpu
);
5908 /* Must be exiting, otherwise would be on tasklist. */
5909 BUG_ON(!p
->exit_state
);
5911 /* Cannot have done final schedule yet: would have vanished. */
5912 BUG_ON(p
->state
== TASK_DEAD
);
5917 * Drop lock around migration; if someone else moves it,
5918 * that's OK. No task can be added to this CPU, so iteration is
5921 spin_unlock_irq(&rq
->lock
);
5922 move_task_off_dead_cpu(dead_cpu
, p
);
5923 spin_lock_irq(&rq
->lock
);
5928 /* release_task() removes task from tasklist, so we won't find dead tasks. */
5929 static void migrate_dead_tasks(unsigned int dead_cpu
)
5931 struct rq
*rq
= cpu_rq(dead_cpu
);
5932 struct task_struct
*next
;
5935 if (!rq
->nr_running
)
5937 update_rq_clock(rq
);
5938 next
= pick_next_task(rq
, rq
->curr
);
5941 migrate_dead(dead_cpu
, next
);
5945 #endif /* CONFIG_HOTPLUG_CPU */
5947 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5949 static struct ctl_table sd_ctl_dir
[] = {
5951 .procname
= "sched_domain",
5957 static struct ctl_table sd_ctl_root
[] = {
5959 .ctl_name
= CTL_KERN
,
5960 .procname
= "kernel",
5962 .child
= sd_ctl_dir
,
5967 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
5969 struct ctl_table
*entry
=
5970 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
5975 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
5977 struct ctl_table
*entry
;
5980 * In the intermediate directories, both the child directory and
5981 * procname are dynamically allocated and could fail but the mode
5982 * will always be set. In the lowest directory the names are
5983 * static strings and all have proc handlers.
5985 for (entry
= *tablep
; entry
->mode
; entry
++) {
5987 sd_free_ctl_entry(&entry
->child
);
5988 if (entry
->proc_handler
== NULL
)
5989 kfree(entry
->procname
);
5997 set_table_entry(struct ctl_table
*entry
,
5998 const char *procname
, void *data
, int maxlen
,
5999 mode_t mode
, proc_handler
*proc_handler
)
6001 entry
->procname
= procname
;
6003 entry
->maxlen
= maxlen
;
6005 entry
->proc_handler
= proc_handler
;
6008 static struct ctl_table
*
6009 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
6011 struct ctl_table
*table
= sd_alloc_ctl_entry(12);
6016 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
6017 sizeof(long), 0644, proc_doulongvec_minmax
);
6018 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
6019 sizeof(long), 0644, proc_doulongvec_minmax
);
6020 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
6021 sizeof(int), 0644, proc_dointvec_minmax
);
6022 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
6023 sizeof(int), 0644, proc_dointvec_minmax
);
6024 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
6025 sizeof(int), 0644, proc_dointvec_minmax
);
6026 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
6027 sizeof(int), 0644, proc_dointvec_minmax
);
6028 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
6029 sizeof(int), 0644, proc_dointvec_minmax
);
6030 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
6031 sizeof(int), 0644, proc_dointvec_minmax
);
6032 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
6033 sizeof(int), 0644, proc_dointvec_minmax
);
6034 set_table_entry(&table
[9], "cache_nice_tries",
6035 &sd
->cache_nice_tries
,
6036 sizeof(int), 0644, proc_dointvec_minmax
);
6037 set_table_entry(&table
[10], "flags", &sd
->flags
,
6038 sizeof(int), 0644, proc_dointvec_minmax
);
6039 /* &table[11] is terminator */
6044 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
6046 struct ctl_table
*entry
, *table
;
6047 struct sched_domain
*sd
;
6048 int domain_num
= 0, i
;
6051 for_each_domain(cpu
, sd
)
6053 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
6058 for_each_domain(cpu
, sd
) {
6059 snprintf(buf
, 32, "domain%d", i
);
6060 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6062 entry
->child
= sd_alloc_ctl_domain_table(sd
);
6069 static struct ctl_table_header
*sd_sysctl_header
;
6070 static void register_sched_domain_sysctl(void)
6072 int i
, cpu_num
= num_online_cpus();
6073 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
6076 WARN_ON(sd_ctl_dir
[0].child
);
6077 sd_ctl_dir
[0].child
= entry
;
6082 for_each_online_cpu(i
) {
6083 snprintf(buf
, 32, "cpu%d", i
);
6084 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6086 entry
->child
= sd_alloc_ctl_cpu_table(i
);
6090 WARN_ON(sd_sysctl_header
);
6091 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
6094 /* may be called multiple times per register */
6095 static void unregister_sched_domain_sysctl(void)
6097 if (sd_sysctl_header
)
6098 unregister_sysctl_table(sd_sysctl_header
);
6099 sd_sysctl_header
= NULL
;
6100 if (sd_ctl_dir
[0].child
)
6101 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
6104 static void register_sched_domain_sysctl(void)
6107 static void unregister_sched_domain_sysctl(void)
6113 * migration_call - callback that gets triggered when a CPU is added.
6114 * Here we can start up the necessary migration thread for the new CPU.
6116 static int __cpuinit
6117 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
6119 struct task_struct
*p
;
6120 int cpu
= (long)hcpu
;
6121 unsigned long flags
;
6126 case CPU_UP_PREPARE
:
6127 case CPU_UP_PREPARE_FROZEN
:
6128 p
= kthread_create(migration_thread
, hcpu
, "migration/%d", cpu
);
6131 kthread_bind(p
, cpu
);
6132 /* Must be high prio: stop_machine expects to yield to it. */
6133 rq
= task_rq_lock(p
, &flags
);
6134 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
6135 task_rq_unlock(rq
, &flags
);
6136 cpu_rq(cpu
)->migration_thread
= p
;
6140 case CPU_ONLINE_FROZEN
:
6141 /* Strictly unnecessary, as first user will wake it. */
6142 wake_up_process(cpu_rq(cpu
)->migration_thread
);
6144 /* Update our root-domain */
6146 spin_lock_irqsave(&rq
->lock
, flags
);
6148 BUG_ON(!cpu_isset(cpu
, rq
->rd
->span
));
6149 cpu_set(cpu
, rq
->rd
->online
);
6151 spin_unlock_irqrestore(&rq
->lock
, flags
);
6154 #ifdef CONFIG_HOTPLUG_CPU
6155 case CPU_UP_CANCELED
:
6156 case CPU_UP_CANCELED_FROZEN
:
6157 if (!cpu_rq(cpu
)->migration_thread
)
6159 /* Unbind it from offline cpu so it can run. Fall thru. */
6160 kthread_bind(cpu_rq(cpu
)->migration_thread
,
6161 any_online_cpu(cpu_online_map
));
6162 kthread_stop(cpu_rq(cpu
)->migration_thread
);
6163 cpu_rq(cpu
)->migration_thread
= NULL
;
6167 case CPU_DEAD_FROZEN
:
6168 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
6169 migrate_live_tasks(cpu
);
6171 kthread_stop(rq
->migration_thread
);
6172 rq
->migration_thread
= NULL
;
6173 /* Idle task back to normal (off runqueue, low prio) */
6174 spin_lock_irq(&rq
->lock
);
6175 update_rq_clock(rq
);
6176 deactivate_task(rq
, rq
->idle
, 0);
6177 rq
->idle
->static_prio
= MAX_PRIO
;
6178 __setscheduler(rq
, rq
->idle
, SCHED_NORMAL
, 0);
6179 rq
->idle
->sched_class
= &idle_sched_class
;
6180 migrate_dead_tasks(cpu
);
6181 spin_unlock_irq(&rq
->lock
);
6183 migrate_nr_uninterruptible(rq
);
6184 BUG_ON(rq
->nr_running
!= 0);
6187 * No need to migrate the tasks: it was best-effort if
6188 * they didn't take sched_hotcpu_mutex. Just wake up
6191 spin_lock_irq(&rq
->lock
);
6192 while (!list_empty(&rq
->migration_queue
)) {
6193 struct migration_req
*req
;
6195 req
= list_entry(rq
->migration_queue
.next
,
6196 struct migration_req
, list
);
6197 list_del_init(&req
->list
);
6198 complete(&req
->done
);
6200 spin_unlock_irq(&rq
->lock
);
6204 case CPU_DYING_FROZEN
:
6205 /* Update our root-domain */
6207 spin_lock_irqsave(&rq
->lock
, flags
);
6209 BUG_ON(!cpu_isset(cpu
, rq
->rd
->span
));
6210 cpu_clear(cpu
, rq
->rd
->online
);
6212 spin_unlock_irqrestore(&rq
->lock
, flags
);
6219 /* Register at highest priority so that task migration (migrate_all_tasks)
6220 * happens before everything else.
6222 static struct notifier_block __cpuinitdata migration_notifier
= {
6223 .notifier_call
= migration_call
,
6227 void __init
migration_init(void)
6229 void *cpu
= (void *)(long)smp_processor_id();
6232 /* Start one for the boot CPU: */
6233 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
6234 BUG_ON(err
== NOTIFY_BAD
);
6235 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
6236 register_cpu_notifier(&migration_notifier
);
6242 #ifdef CONFIG_SCHED_DEBUG
6244 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
6245 cpumask_t
*groupmask
)
6247 struct sched_group
*group
= sd
->groups
;
6250 cpulist_scnprintf(str
, sizeof(str
), sd
->span
);
6251 cpus_clear(*groupmask
);
6253 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
6255 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
6256 printk("does not load-balance\n");
6258 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
6263 printk(KERN_CONT
"span %s\n", str
);
6265 if (!cpu_isset(cpu
, sd
->span
)) {
6266 printk(KERN_ERR
"ERROR: domain->span does not contain "
6269 if (!cpu_isset(cpu
, group
->cpumask
)) {
6270 printk(KERN_ERR
"ERROR: domain->groups does not contain"
6274 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
6278 printk(KERN_ERR
"ERROR: group is NULL\n");
6282 if (!group
->__cpu_power
) {
6283 printk(KERN_CONT
"\n");
6284 printk(KERN_ERR
"ERROR: domain->cpu_power not "
6289 if (!cpus_weight(group
->cpumask
)) {
6290 printk(KERN_CONT
"\n");
6291 printk(KERN_ERR
"ERROR: empty group\n");
6295 if (cpus_intersects(*groupmask
, group
->cpumask
)) {
6296 printk(KERN_CONT
"\n");
6297 printk(KERN_ERR
"ERROR: repeated CPUs\n");
6301 cpus_or(*groupmask
, *groupmask
, group
->cpumask
);
6303 cpulist_scnprintf(str
, sizeof(str
), group
->cpumask
);
6304 printk(KERN_CONT
" %s", str
);
6306 group
= group
->next
;
6307 } while (group
!= sd
->groups
);
6308 printk(KERN_CONT
"\n");
6310 if (!cpus_equal(sd
->span
, *groupmask
))
6311 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
6313 if (sd
->parent
&& !cpus_subset(*groupmask
, sd
->parent
->span
))
6314 printk(KERN_ERR
"ERROR: parent span is not a superset "
6315 "of domain->span\n");
6319 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
6321 cpumask_t
*groupmask
;
6325 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
6329 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
6331 groupmask
= kmalloc(sizeof(cpumask_t
), GFP_KERNEL
);
6333 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
6338 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
6348 # define sched_domain_debug(sd, cpu) do { } while (0)
6351 static int sd_degenerate(struct sched_domain
*sd
)
6353 if (cpus_weight(sd
->span
) == 1)
6356 /* Following flags need at least 2 groups */
6357 if (sd
->flags
& (SD_LOAD_BALANCE
|
6358 SD_BALANCE_NEWIDLE
|
6362 SD_SHARE_PKG_RESOURCES
)) {
6363 if (sd
->groups
!= sd
->groups
->next
)
6367 /* Following flags don't use groups */
6368 if (sd
->flags
& (SD_WAKE_IDLE
|
6377 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
6379 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
6381 if (sd_degenerate(parent
))
6384 if (!cpus_equal(sd
->span
, parent
->span
))
6387 /* Does parent contain flags not in child? */
6388 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
6389 if (cflags
& SD_WAKE_AFFINE
)
6390 pflags
&= ~SD_WAKE_BALANCE
;
6391 /* Flags needing groups don't count if only 1 group in parent */
6392 if (parent
->groups
== parent
->groups
->next
) {
6393 pflags
&= ~(SD_LOAD_BALANCE
|
6394 SD_BALANCE_NEWIDLE
|
6398 SD_SHARE_PKG_RESOURCES
);
6400 if (~cflags
& pflags
)
6406 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
6408 unsigned long flags
;
6409 const struct sched_class
*class;
6411 spin_lock_irqsave(&rq
->lock
, flags
);
6414 struct root_domain
*old_rd
= rq
->rd
;
6416 for (class = sched_class_highest
; class; class = class->next
) {
6417 if (class->leave_domain
)
6418 class->leave_domain(rq
);
6421 cpu_clear(rq
->cpu
, old_rd
->span
);
6422 cpu_clear(rq
->cpu
, old_rd
->online
);
6424 if (atomic_dec_and_test(&old_rd
->refcount
))
6428 atomic_inc(&rd
->refcount
);
6431 cpu_set(rq
->cpu
, rd
->span
);
6432 if (cpu_isset(rq
->cpu
, cpu_online_map
))
6433 cpu_set(rq
->cpu
, rd
->online
);
6435 for (class = sched_class_highest
; class; class = class->next
) {
6436 if (class->join_domain
)
6437 class->join_domain(rq
);
6440 spin_unlock_irqrestore(&rq
->lock
, flags
);
6443 static void init_rootdomain(struct root_domain
*rd
)
6445 memset(rd
, 0, sizeof(*rd
));
6447 cpus_clear(rd
->span
);
6448 cpus_clear(rd
->online
);
6451 static void init_defrootdomain(void)
6453 init_rootdomain(&def_root_domain
);
6454 atomic_set(&def_root_domain
.refcount
, 1);
6457 static struct root_domain
*alloc_rootdomain(void)
6459 struct root_domain
*rd
;
6461 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
6465 init_rootdomain(rd
);
6471 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6472 * hold the hotplug lock.
6475 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
6477 struct rq
*rq
= cpu_rq(cpu
);
6478 struct sched_domain
*tmp
;
6480 /* Remove the sched domains which do not contribute to scheduling. */
6481 for (tmp
= sd
; tmp
; tmp
= tmp
->parent
) {
6482 struct sched_domain
*parent
= tmp
->parent
;
6485 if (sd_parent_degenerate(tmp
, parent
)) {
6486 tmp
->parent
= parent
->parent
;
6488 parent
->parent
->child
= tmp
;
6492 if (sd
&& sd_degenerate(sd
)) {
6498 sched_domain_debug(sd
, cpu
);
6500 rq_attach_root(rq
, rd
);
6501 rcu_assign_pointer(rq
->sd
, sd
);
6504 /* cpus with isolated domains */
6505 static cpumask_t cpu_isolated_map
= CPU_MASK_NONE
;
6507 /* Setup the mask of cpus configured for isolated domains */
6508 static int __init
isolated_cpu_setup(char *str
)
6510 int ints
[NR_CPUS
], i
;
6512 str
= get_options(str
, ARRAY_SIZE(ints
), ints
);
6513 cpus_clear(cpu_isolated_map
);
6514 for (i
= 1; i
<= ints
[0]; i
++)
6515 if (ints
[i
] < NR_CPUS
)
6516 cpu_set(ints
[i
], cpu_isolated_map
);
6520 __setup("isolcpus=", isolated_cpu_setup
);
6523 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
6524 * to a function which identifies what group(along with sched group) a CPU
6525 * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS
6526 * (due to the fact that we keep track of groups covered with a cpumask_t).
6528 * init_sched_build_groups will build a circular linked list of the groups
6529 * covered by the given span, and will set each group's ->cpumask correctly,
6530 * and ->cpu_power to 0.
6533 init_sched_build_groups(const cpumask_t
*span
, const cpumask_t
*cpu_map
,
6534 int (*group_fn
)(int cpu
, const cpumask_t
*cpu_map
,
6535 struct sched_group
**sg
,
6536 cpumask_t
*tmpmask
),
6537 cpumask_t
*covered
, cpumask_t
*tmpmask
)
6539 struct sched_group
*first
= NULL
, *last
= NULL
;
6542 cpus_clear(*covered
);
6544 for_each_cpu_mask(i
, *span
) {
6545 struct sched_group
*sg
;
6546 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
6549 if (cpu_isset(i
, *covered
))
6552 cpus_clear(sg
->cpumask
);
6553 sg
->__cpu_power
= 0;
6555 for_each_cpu_mask(j
, *span
) {
6556 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
6559 cpu_set(j
, *covered
);
6560 cpu_set(j
, sg
->cpumask
);
6571 #define SD_NODES_PER_DOMAIN 16
6576 * find_next_best_node - find the next node to include in a sched_domain
6577 * @node: node whose sched_domain we're building
6578 * @used_nodes: nodes already in the sched_domain
6580 * Find the next node to include in a given scheduling domain. Simply
6581 * finds the closest node not already in the @used_nodes map.
6583 * Should use nodemask_t.
6585 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
6587 int i
, n
, val
, min_val
, best_node
= 0;
6591 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6592 /* Start at @node */
6593 n
= (node
+ i
) % MAX_NUMNODES
;
6595 if (!nr_cpus_node(n
))
6598 /* Skip already used nodes */
6599 if (node_isset(n
, *used_nodes
))
6602 /* Simple min distance search */
6603 val
= node_distance(node
, n
);
6605 if (val
< min_val
) {
6611 node_set(best_node
, *used_nodes
);
6616 * sched_domain_node_span - get a cpumask for a node's sched_domain
6617 * @node: node whose cpumask we're constructing
6618 * @span: resulting cpumask
6620 * Given a node, construct a good cpumask for its sched_domain to span. It
6621 * should be one that prevents unnecessary balancing, but also spreads tasks
6624 static void sched_domain_node_span(int node
, cpumask_t
*span
)
6626 nodemask_t used_nodes
;
6627 node_to_cpumask_ptr(nodemask
, node
);
6631 nodes_clear(used_nodes
);
6633 cpus_or(*span
, *span
, *nodemask
);
6634 node_set(node
, used_nodes
);
6636 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
6637 int next_node
= find_next_best_node(node
, &used_nodes
);
6639 node_to_cpumask_ptr_next(nodemask
, next_node
);
6640 cpus_or(*span
, *span
, *nodemask
);
6645 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
6648 * SMT sched-domains:
6650 #ifdef CONFIG_SCHED_SMT
6651 static DEFINE_PER_CPU(struct sched_domain
, cpu_domains
);
6652 static DEFINE_PER_CPU(struct sched_group
, sched_group_cpus
);
6655 cpu_to_cpu_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6659 *sg
= &per_cpu(sched_group_cpus
, cpu
);
6665 * multi-core sched-domains:
6667 #ifdef CONFIG_SCHED_MC
6668 static DEFINE_PER_CPU(struct sched_domain
, core_domains
);
6669 static DEFINE_PER_CPU(struct sched_group
, sched_group_core
);
6672 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
6674 cpu_to_core_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6679 *mask
= per_cpu(cpu_sibling_map
, cpu
);
6680 cpus_and(*mask
, *mask
, *cpu_map
);
6681 group
= first_cpu(*mask
);
6683 *sg
= &per_cpu(sched_group_core
, group
);
6686 #elif defined(CONFIG_SCHED_MC)
6688 cpu_to_core_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6692 *sg
= &per_cpu(sched_group_core
, cpu
);
6697 static DEFINE_PER_CPU(struct sched_domain
, phys_domains
);
6698 static DEFINE_PER_CPU(struct sched_group
, sched_group_phys
);
6701 cpu_to_phys_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6705 #ifdef CONFIG_SCHED_MC
6706 *mask
= cpu_coregroup_map(cpu
);
6707 cpus_and(*mask
, *mask
, *cpu_map
);
6708 group
= first_cpu(*mask
);
6709 #elif defined(CONFIG_SCHED_SMT)
6710 *mask
= per_cpu(cpu_sibling_map
, cpu
);
6711 cpus_and(*mask
, *mask
, *cpu_map
);
6712 group
= first_cpu(*mask
);
6717 *sg
= &per_cpu(sched_group_phys
, group
);
6723 * The init_sched_build_groups can't handle what we want to do with node
6724 * groups, so roll our own. Now each node has its own list of groups which
6725 * gets dynamically allocated.
6727 static DEFINE_PER_CPU(struct sched_domain
, node_domains
);
6728 static struct sched_group
***sched_group_nodes_bycpu
;
6730 static DEFINE_PER_CPU(struct sched_domain
, allnodes_domains
);
6731 static DEFINE_PER_CPU(struct sched_group
, sched_group_allnodes
);
6733 static int cpu_to_allnodes_group(int cpu
, const cpumask_t
*cpu_map
,
6734 struct sched_group
**sg
, cpumask_t
*nodemask
)
6738 *nodemask
= node_to_cpumask(cpu_to_node(cpu
));
6739 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6740 group
= first_cpu(*nodemask
);
6743 *sg
= &per_cpu(sched_group_allnodes
, group
);
6747 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
6749 struct sched_group
*sg
= group_head
;
6755 for_each_cpu_mask(j
, sg
->cpumask
) {
6756 struct sched_domain
*sd
;
6758 sd
= &per_cpu(phys_domains
, j
);
6759 if (j
!= first_cpu(sd
->groups
->cpumask
)) {
6761 * Only add "power" once for each
6767 sg_inc_cpu_power(sg
, sd
->groups
->__cpu_power
);
6770 } while (sg
!= group_head
);
6775 /* Free memory allocated for various sched_group structures */
6776 static void free_sched_groups(const cpumask_t
*cpu_map
, cpumask_t
*nodemask
)
6780 for_each_cpu_mask(cpu
, *cpu_map
) {
6781 struct sched_group
**sched_group_nodes
6782 = sched_group_nodes_bycpu
[cpu
];
6784 if (!sched_group_nodes
)
6787 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6788 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
6790 *nodemask
= node_to_cpumask(i
);
6791 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6792 if (cpus_empty(*nodemask
))
6802 if (oldsg
!= sched_group_nodes
[i
])
6805 kfree(sched_group_nodes
);
6806 sched_group_nodes_bycpu
[cpu
] = NULL
;
6810 static void free_sched_groups(const cpumask_t
*cpu_map
, cpumask_t
*nodemask
)
6816 * Initialize sched groups cpu_power.
6818 * cpu_power indicates the capacity of sched group, which is used while
6819 * distributing the load between different sched groups in a sched domain.
6820 * Typically cpu_power for all the groups in a sched domain will be same unless
6821 * there are asymmetries in the topology. If there are asymmetries, group
6822 * having more cpu_power will pickup more load compared to the group having
6825 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
6826 * the maximum number of tasks a group can handle in the presence of other idle
6827 * or lightly loaded groups in the same sched domain.
6829 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
6831 struct sched_domain
*child
;
6832 struct sched_group
*group
;
6834 WARN_ON(!sd
|| !sd
->groups
);
6836 if (cpu
!= first_cpu(sd
->groups
->cpumask
))
6841 sd
->groups
->__cpu_power
= 0;
6844 * For perf policy, if the groups in child domain share resources
6845 * (for example cores sharing some portions of the cache hierarchy
6846 * or SMT), then set this domain groups cpu_power such that each group
6847 * can handle only one task, when there are other idle groups in the
6848 * same sched domain.
6850 if (!child
|| (!(sd
->flags
& SD_POWERSAVINGS_BALANCE
) &&
6852 (SD_SHARE_CPUPOWER
| SD_SHARE_PKG_RESOURCES
)))) {
6853 sg_inc_cpu_power(sd
->groups
, SCHED_LOAD_SCALE
);
6858 * add cpu_power of each child group to this groups cpu_power
6860 group
= child
->groups
;
6862 sg_inc_cpu_power(sd
->groups
, group
->__cpu_power
);
6863 group
= group
->next
;
6864 } while (group
!= child
->groups
);
6868 * Initializers for schedule domains
6869 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6872 #define SD_INIT(sd, type) sd_init_##type(sd)
6873 #define SD_INIT_FUNC(type) \
6874 static noinline void sd_init_##type(struct sched_domain *sd) \
6876 memset(sd, 0, sizeof(*sd)); \
6877 *sd = SD_##type##_INIT; \
6878 sd->level = SD_LV_##type; \
6883 SD_INIT_FUNC(ALLNODES
)
6886 #ifdef CONFIG_SCHED_SMT
6887 SD_INIT_FUNC(SIBLING
)
6889 #ifdef CONFIG_SCHED_MC
6894 * To minimize stack usage kmalloc room for cpumasks and share the
6895 * space as the usage in build_sched_domains() dictates. Used only
6896 * if the amount of space is significant.
6899 cpumask_t tmpmask
; /* make this one first */
6902 cpumask_t this_sibling_map
;
6903 cpumask_t this_core_map
;
6905 cpumask_t send_covered
;
6908 cpumask_t domainspan
;
6910 cpumask_t notcovered
;
6915 #define SCHED_CPUMASK_ALLOC 1
6916 #define SCHED_CPUMASK_FREE(v) kfree(v)
6917 #define SCHED_CPUMASK_DECLARE(v) struct allmasks *v
6919 #define SCHED_CPUMASK_ALLOC 0
6920 #define SCHED_CPUMASK_FREE(v)
6921 #define SCHED_CPUMASK_DECLARE(v) struct allmasks _v, *v = &_v
6924 #define SCHED_CPUMASK_VAR(v, a) cpumask_t *v = (cpumask_t *) \
6925 ((unsigned long)(a) + offsetof(struct allmasks, v))
6927 static int default_relax_domain_level
= -1;
6929 static int __init
setup_relax_domain_level(char *str
)
6931 default_relax_domain_level
= simple_strtoul(str
, NULL
, 0);
6934 __setup("relax_domain_level=", setup_relax_domain_level
);
6936 static void set_domain_attribute(struct sched_domain
*sd
,
6937 struct sched_domain_attr
*attr
)
6941 if (!attr
|| attr
->relax_domain_level
< 0) {
6942 if (default_relax_domain_level
< 0)
6945 request
= default_relax_domain_level
;
6947 request
= attr
->relax_domain_level
;
6948 if (request
< sd
->level
) {
6949 /* turn off idle balance on this domain */
6950 sd
->flags
&= ~(SD_WAKE_IDLE
|SD_BALANCE_NEWIDLE
);
6952 /* turn on idle balance on this domain */
6953 sd
->flags
|= (SD_WAKE_IDLE_FAR
|SD_BALANCE_NEWIDLE
);
6958 * Build sched domains for a given set of cpus and attach the sched domains
6959 * to the individual cpus
6961 static int __build_sched_domains(const cpumask_t
*cpu_map
,
6962 struct sched_domain_attr
*attr
)
6965 struct root_domain
*rd
;
6966 SCHED_CPUMASK_DECLARE(allmasks
);
6969 struct sched_group
**sched_group_nodes
= NULL
;
6970 int sd_allnodes
= 0;
6973 * Allocate the per-node list of sched groups
6975 sched_group_nodes
= kcalloc(MAX_NUMNODES
, sizeof(struct sched_group
*),
6977 if (!sched_group_nodes
) {
6978 printk(KERN_WARNING
"Can not alloc sched group node list\n");
6983 rd
= alloc_rootdomain();
6985 printk(KERN_WARNING
"Cannot alloc root domain\n");
6987 kfree(sched_group_nodes
);
6992 #if SCHED_CPUMASK_ALLOC
6993 /* get space for all scratch cpumask variables */
6994 allmasks
= kmalloc(sizeof(*allmasks
), GFP_KERNEL
);
6996 printk(KERN_WARNING
"Cannot alloc cpumask array\n");
6999 kfree(sched_group_nodes
);
7004 tmpmask
= (cpumask_t
*)allmasks
;
7008 sched_group_nodes_bycpu
[first_cpu(*cpu_map
)] = sched_group_nodes
;
7012 * Set up domains for cpus specified by the cpu_map.
7014 for_each_cpu_mask(i
, *cpu_map
) {
7015 struct sched_domain
*sd
= NULL
, *p
;
7016 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
7018 *nodemask
= node_to_cpumask(cpu_to_node(i
));
7019 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
7022 if (cpus_weight(*cpu_map
) >
7023 SD_NODES_PER_DOMAIN
*cpus_weight(*nodemask
)) {
7024 sd
= &per_cpu(allnodes_domains
, i
);
7025 SD_INIT(sd
, ALLNODES
);
7026 set_domain_attribute(sd
, attr
);
7027 sd
->span
= *cpu_map
;
7028 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7034 sd
= &per_cpu(node_domains
, i
);
7036 set_domain_attribute(sd
, attr
);
7037 sched_domain_node_span(cpu_to_node(i
), &sd
->span
);
7041 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
7045 sd
= &per_cpu(phys_domains
, i
);
7047 set_domain_attribute(sd
, attr
);
7048 sd
->span
= *nodemask
;
7052 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7054 #ifdef CONFIG_SCHED_MC
7056 sd
= &per_cpu(core_domains
, i
);
7058 set_domain_attribute(sd
, attr
);
7059 sd
->span
= cpu_coregroup_map(i
);
7060 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
7063 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7066 #ifdef CONFIG_SCHED_SMT
7068 sd
= &per_cpu(cpu_domains
, i
);
7069 SD_INIT(sd
, SIBLING
);
7070 set_domain_attribute(sd
, attr
);
7071 sd
->span
= per_cpu(cpu_sibling_map
, i
);
7072 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
7075 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7079 #ifdef CONFIG_SCHED_SMT
7080 /* Set up CPU (sibling) groups */
7081 for_each_cpu_mask(i
, *cpu_map
) {
7082 SCHED_CPUMASK_VAR(this_sibling_map
, allmasks
);
7083 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
7085 *this_sibling_map
= per_cpu(cpu_sibling_map
, i
);
7086 cpus_and(*this_sibling_map
, *this_sibling_map
, *cpu_map
);
7087 if (i
!= first_cpu(*this_sibling_map
))
7090 init_sched_build_groups(this_sibling_map
, cpu_map
,
7092 send_covered
, tmpmask
);
7096 #ifdef CONFIG_SCHED_MC
7097 /* Set up multi-core groups */
7098 for_each_cpu_mask(i
, *cpu_map
) {
7099 SCHED_CPUMASK_VAR(this_core_map
, allmasks
);
7100 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
7102 *this_core_map
= cpu_coregroup_map(i
);
7103 cpus_and(*this_core_map
, *this_core_map
, *cpu_map
);
7104 if (i
!= first_cpu(*this_core_map
))
7107 init_sched_build_groups(this_core_map
, cpu_map
,
7109 send_covered
, tmpmask
);
7113 /* Set up physical groups */
7114 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
7115 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
7116 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
7118 *nodemask
= node_to_cpumask(i
);
7119 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
7120 if (cpus_empty(*nodemask
))
7123 init_sched_build_groups(nodemask
, cpu_map
,
7125 send_covered
, tmpmask
);
7129 /* Set up node groups */
7131 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
7133 init_sched_build_groups(cpu_map
, cpu_map
,
7134 &cpu_to_allnodes_group
,
7135 send_covered
, tmpmask
);
7138 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
7139 /* Set up node groups */
7140 struct sched_group
*sg
, *prev
;
7141 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
7142 SCHED_CPUMASK_VAR(domainspan
, allmasks
);
7143 SCHED_CPUMASK_VAR(covered
, allmasks
);
7146 *nodemask
= node_to_cpumask(i
);
7147 cpus_clear(*covered
);
7149 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
7150 if (cpus_empty(*nodemask
)) {
7151 sched_group_nodes
[i
] = NULL
;
7155 sched_domain_node_span(i
, domainspan
);
7156 cpus_and(*domainspan
, *domainspan
, *cpu_map
);
7158 sg
= kmalloc_node(sizeof(struct sched_group
), GFP_KERNEL
, i
);
7160 printk(KERN_WARNING
"Can not alloc domain group for "
7164 sched_group_nodes
[i
] = sg
;
7165 for_each_cpu_mask(j
, *nodemask
) {
7166 struct sched_domain
*sd
;
7168 sd
= &per_cpu(node_domains
, j
);
7171 sg
->__cpu_power
= 0;
7172 sg
->cpumask
= *nodemask
;
7174 cpus_or(*covered
, *covered
, *nodemask
);
7177 for (j
= 0; j
< MAX_NUMNODES
; j
++) {
7178 SCHED_CPUMASK_VAR(notcovered
, allmasks
);
7179 int n
= (i
+ j
) % MAX_NUMNODES
;
7180 node_to_cpumask_ptr(pnodemask
, n
);
7182 cpus_complement(*notcovered
, *covered
);
7183 cpus_and(*tmpmask
, *notcovered
, *cpu_map
);
7184 cpus_and(*tmpmask
, *tmpmask
, *domainspan
);
7185 if (cpus_empty(*tmpmask
))
7188 cpus_and(*tmpmask
, *tmpmask
, *pnodemask
);
7189 if (cpus_empty(*tmpmask
))
7192 sg
= kmalloc_node(sizeof(struct sched_group
),
7196 "Can not alloc domain group for node %d\n", j
);
7199 sg
->__cpu_power
= 0;
7200 sg
->cpumask
= *tmpmask
;
7201 sg
->next
= prev
->next
;
7202 cpus_or(*covered
, *covered
, *tmpmask
);
7209 /* Calculate CPU power for physical packages and nodes */
7210 #ifdef CONFIG_SCHED_SMT
7211 for_each_cpu_mask(i
, *cpu_map
) {
7212 struct sched_domain
*sd
= &per_cpu(cpu_domains
, i
);
7214 init_sched_groups_power(i
, sd
);
7217 #ifdef CONFIG_SCHED_MC
7218 for_each_cpu_mask(i
, *cpu_map
) {
7219 struct sched_domain
*sd
= &per_cpu(core_domains
, i
);
7221 init_sched_groups_power(i
, sd
);
7225 for_each_cpu_mask(i
, *cpu_map
) {
7226 struct sched_domain
*sd
= &per_cpu(phys_domains
, i
);
7228 init_sched_groups_power(i
, sd
);
7232 for (i
= 0; i
< MAX_NUMNODES
; i
++)
7233 init_numa_sched_groups_power(sched_group_nodes
[i
]);
7236 struct sched_group
*sg
;
7238 cpu_to_allnodes_group(first_cpu(*cpu_map
), cpu_map
, &sg
,
7240 init_numa_sched_groups_power(sg
);
7244 /* Attach the domains */
7245 for_each_cpu_mask(i
, *cpu_map
) {
7246 struct sched_domain
*sd
;
7247 #ifdef CONFIG_SCHED_SMT
7248 sd
= &per_cpu(cpu_domains
, i
);
7249 #elif defined(CONFIG_SCHED_MC)
7250 sd
= &per_cpu(core_domains
, i
);
7252 sd
= &per_cpu(phys_domains
, i
);
7254 cpu_attach_domain(sd
, rd
, i
);
7257 SCHED_CPUMASK_FREE((void *)allmasks
);
7262 free_sched_groups(cpu_map
, tmpmask
);
7263 SCHED_CPUMASK_FREE((void *)allmasks
);
7268 static int build_sched_domains(const cpumask_t
*cpu_map
)
7270 return __build_sched_domains(cpu_map
, NULL
);
7273 static cpumask_t
*doms_cur
; /* current sched domains */
7274 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
7275 static struct sched_domain_attr
*dattr_cur
;
7276 /* attribues of custom domains in 'doms_cur' */
7279 * Special case: If a kmalloc of a doms_cur partition (array of
7280 * cpumask_t) fails, then fallback to a single sched domain,
7281 * as determined by the single cpumask_t fallback_doms.
7283 static cpumask_t fallback_doms
;
7285 void __attribute__((weak
)) arch_update_cpu_topology(void)
7290 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7291 * For now this just excludes isolated cpus, but could be used to
7292 * exclude other special cases in the future.
7294 static int arch_init_sched_domains(const cpumask_t
*cpu_map
)
7298 arch_update_cpu_topology();
7300 doms_cur
= kmalloc(sizeof(cpumask_t
), GFP_KERNEL
);
7302 doms_cur
= &fallback_doms
;
7303 cpus_andnot(*doms_cur
, *cpu_map
, cpu_isolated_map
);
7305 err
= build_sched_domains(doms_cur
);
7306 register_sched_domain_sysctl();
7311 static void arch_destroy_sched_domains(const cpumask_t
*cpu_map
,
7314 free_sched_groups(cpu_map
, tmpmask
);
7318 * Detach sched domains from a group of cpus specified in cpu_map
7319 * These cpus will now be attached to the NULL domain
7321 static void detach_destroy_domains(const cpumask_t
*cpu_map
)
7326 unregister_sched_domain_sysctl();
7328 for_each_cpu_mask(i
, *cpu_map
)
7329 cpu_attach_domain(NULL
, &def_root_domain
, i
);
7330 synchronize_sched();
7331 arch_destroy_sched_domains(cpu_map
, &tmpmask
);
7334 /* handle null as "default" */
7335 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
7336 struct sched_domain_attr
*new, int idx_new
)
7338 struct sched_domain_attr tmp
;
7345 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
7346 new ? (new + idx_new
) : &tmp
,
7347 sizeof(struct sched_domain_attr
));
7351 * Partition sched domains as specified by the 'ndoms_new'
7352 * cpumasks in the array doms_new[] of cpumasks. This compares
7353 * doms_new[] to the current sched domain partitioning, doms_cur[].
7354 * It destroys each deleted domain and builds each new domain.
7356 * 'doms_new' is an array of cpumask_t's of length 'ndoms_new'.
7357 * The masks don't intersect (don't overlap.) We should setup one
7358 * sched domain for each mask. CPUs not in any of the cpumasks will
7359 * not be load balanced. If the same cpumask appears both in the
7360 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7363 * The passed in 'doms_new' should be kmalloc'd. This routine takes
7364 * ownership of it and will kfree it when done with it. If the caller
7365 * failed the kmalloc call, then it can pass in doms_new == NULL,
7366 * and partition_sched_domains() will fallback to the single partition
7369 * Call with hotplug lock held
7371 void partition_sched_domains(int ndoms_new
, cpumask_t
*doms_new
,
7372 struct sched_domain_attr
*dattr_new
)
7376 mutex_lock(&sched_domains_mutex
);
7378 /* always unregister in case we don't destroy any domains */
7379 unregister_sched_domain_sysctl();
7381 if (doms_new
== NULL
) {
7383 doms_new
= &fallback_doms
;
7384 cpus_andnot(doms_new
[0], cpu_online_map
, cpu_isolated_map
);
7388 /* Destroy deleted domains */
7389 for (i
= 0; i
< ndoms_cur
; i
++) {
7390 for (j
= 0; j
< ndoms_new
; j
++) {
7391 if (cpus_equal(doms_cur
[i
], doms_new
[j
])
7392 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
7395 /* no match - a current sched domain not in new doms_new[] */
7396 detach_destroy_domains(doms_cur
+ i
);
7401 /* Build new domains */
7402 for (i
= 0; i
< ndoms_new
; i
++) {
7403 for (j
= 0; j
< ndoms_cur
; j
++) {
7404 if (cpus_equal(doms_new
[i
], doms_cur
[j
])
7405 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
7408 /* no match - add a new doms_new */
7409 __build_sched_domains(doms_new
+ i
,
7410 dattr_new
? dattr_new
+ i
: NULL
);
7415 /* Remember the new sched domains */
7416 if (doms_cur
!= &fallback_doms
)
7418 kfree(dattr_cur
); /* kfree(NULL) is safe */
7419 doms_cur
= doms_new
;
7420 dattr_cur
= dattr_new
;
7421 ndoms_cur
= ndoms_new
;
7423 register_sched_domain_sysctl();
7425 mutex_unlock(&sched_domains_mutex
);
7428 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7429 int arch_reinit_sched_domains(void)
7434 mutex_lock(&sched_domains_mutex
);
7435 detach_destroy_domains(&cpu_online_map
);
7436 err
= arch_init_sched_domains(&cpu_online_map
);
7437 mutex_unlock(&sched_domains_mutex
);
7443 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
7447 if (buf
[0] != '0' && buf
[0] != '1')
7451 sched_smt_power_savings
= (buf
[0] == '1');
7453 sched_mc_power_savings
= (buf
[0] == '1');
7455 ret
= arch_reinit_sched_domains();
7457 return ret
? ret
: count
;
7460 #ifdef CONFIG_SCHED_MC
7461 static ssize_t
sched_mc_power_savings_show(struct sys_device
*dev
, char *page
)
7463 return sprintf(page
, "%u\n", sched_mc_power_savings
);
7465 static ssize_t
sched_mc_power_savings_store(struct sys_device
*dev
,
7466 const char *buf
, size_t count
)
7468 return sched_power_savings_store(buf
, count
, 0);
7470 static SYSDEV_ATTR(sched_mc_power_savings
, 0644, sched_mc_power_savings_show
,
7471 sched_mc_power_savings_store
);
7474 #ifdef CONFIG_SCHED_SMT
7475 static ssize_t
sched_smt_power_savings_show(struct sys_device
*dev
, char *page
)
7477 return sprintf(page
, "%u\n", sched_smt_power_savings
);
7479 static ssize_t
sched_smt_power_savings_store(struct sys_device
*dev
,
7480 const char *buf
, size_t count
)
7482 return sched_power_savings_store(buf
, count
, 1);
7484 static SYSDEV_ATTR(sched_smt_power_savings
, 0644, sched_smt_power_savings_show
,
7485 sched_smt_power_savings_store
);
7488 int sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
7492 #ifdef CONFIG_SCHED_SMT
7494 err
= sysfs_create_file(&cls
->kset
.kobj
,
7495 &attr_sched_smt_power_savings
.attr
);
7497 #ifdef CONFIG_SCHED_MC
7498 if (!err
&& mc_capable())
7499 err
= sysfs_create_file(&cls
->kset
.kobj
,
7500 &attr_sched_mc_power_savings
.attr
);
7507 * Force a reinitialization of the sched domains hierarchy. The domains
7508 * and groups cannot be updated in place without racing with the balancing
7509 * code, so we temporarily attach all running cpus to the NULL domain
7510 * which will prevent rebalancing while the sched domains are recalculated.
7512 static int update_sched_domains(struct notifier_block
*nfb
,
7513 unsigned long action
, void *hcpu
)
7516 case CPU_UP_PREPARE
:
7517 case CPU_UP_PREPARE_FROZEN
:
7518 case CPU_DOWN_PREPARE
:
7519 case CPU_DOWN_PREPARE_FROZEN
:
7520 detach_destroy_domains(&cpu_online_map
);
7523 case CPU_UP_CANCELED
:
7524 case CPU_UP_CANCELED_FROZEN
:
7525 case CPU_DOWN_FAILED
:
7526 case CPU_DOWN_FAILED_FROZEN
:
7528 case CPU_ONLINE_FROZEN
:
7530 case CPU_DEAD_FROZEN
:
7532 * Fall through and re-initialise the domains.
7539 /* The hotplug lock is already held by cpu_up/cpu_down */
7540 arch_init_sched_domains(&cpu_online_map
);
7545 void __init
sched_init_smp(void)
7547 cpumask_t non_isolated_cpus
;
7549 #if defined(CONFIG_NUMA)
7550 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
7552 BUG_ON(sched_group_nodes_bycpu
== NULL
);
7555 mutex_lock(&sched_domains_mutex
);
7556 arch_init_sched_domains(&cpu_online_map
);
7557 cpus_andnot(non_isolated_cpus
, cpu_possible_map
, cpu_isolated_map
);
7558 if (cpus_empty(non_isolated_cpus
))
7559 cpu_set(smp_processor_id(), non_isolated_cpus
);
7560 mutex_unlock(&sched_domains_mutex
);
7562 /* XXX: Theoretical race here - CPU may be hotplugged now */
7563 hotcpu_notifier(update_sched_domains
, 0);
7566 /* Move init over to a non-isolated CPU */
7567 if (set_cpus_allowed_ptr(current
, &non_isolated_cpus
) < 0)
7569 sched_init_granularity();
7572 void __init
sched_init_smp(void)
7574 sched_init_granularity();
7576 #endif /* CONFIG_SMP */
7578 int in_sched_functions(unsigned long addr
)
7580 return in_lock_functions(addr
) ||
7581 (addr
>= (unsigned long)__sched_text_start
7582 && addr
< (unsigned long)__sched_text_end
);
7585 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
7587 cfs_rq
->tasks_timeline
= RB_ROOT
;
7588 INIT_LIST_HEAD(&cfs_rq
->tasks
);
7589 #ifdef CONFIG_FAIR_GROUP_SCHED
7592 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
7595 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
7597 struct rt_prio_array
*array
;
7600 array
= &rt_rq
->active
;
7601 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
7602 INIT_LIST_HEAD(array
->queue
+ i
);
7603 __clear_bit(i
, array
->bitmap
);
7605 /* delimiter for bitsearch: */
7606 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
7608 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
7609 rt_rq
->highest_prio
= MAX_RT_PRIO
;
7612 rt_rq
->rt_nr_migratory
= 0;
7613 rt_rq
->overloaded
= 0;
7617 rt_rq
->rt_throttled
= 0;
7618 rt_rq
->rt_runtime
= 0;
7619 spin_lock_init(&rt_rq
->rt_runtime_lock
);
7621 #ifdef CONFIG_RT_GROUP_SCHED
7622 rt_rq
->rt_nr_boosted
= 0;
7627 #ifdef CONFIG_FAIR_GROUP_SCHED
7628 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
7629 struct sched_entity
*se
, int cpu
, int add
,
7630 struct sched_entity
*parent
)
7632 struct rq
*rq
= cpu_rq(cpu
);
7633 tg
->cfs_rq
[cpu
] = cfs_rq
;
7634 init_cfs_rq(cfs_rq
, rq
);
7637 list_add(&cfs_rq
->leaf_cfs_rq_list
, &rq
->leaf_cfs_rq_list
);
7640 /* se could be NULL for init_task_group */
7645 se
->cfs_rq
= &rq
->cfs
;
7647 se
->cfs_rq
= parent
->my_q
;
7650 se
->load
.weight
= tg
->shares
;
7651 se
->load
.inv_weight
= 0;
7652 se
->parent
= parent
;
7656 #ifdef CONFIG_RT_GROUP_SCHED
7657 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
7658 struct sched_rt_entity
*rt_se
, int cpu
, int add
,
7659 struct sched_rt_entity
*parent
)
7661 struct rq
*rq
= cpu_rq(cpu
);
7663 tg
->rt_rq
[cpu
] = rt_rq
;
7664 init_rt_rq(rt_rq
, rq
);
7666 rt_rq
->rt_se
= rt_se
;
7667 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7669 list_add(&rt_rq
->leaf_rt_rq_list
, &rq
->leaf_rt_rq_list
);
7671 tg
->rt_se
[cpu
] = rt_se
;
7676 rt_se
->rt_rq
= &rq
->rt
;
7678 rt_se
->rt_rq
= parent
->my_q
;
7680 rt_se
->rt_rq
= &rq
->rt
;
7681 rt_se
->my_q
= rt_rq
;
7682 rt_se
->parent
= parent
;
7683 INIT_LIST_HEAD(&rt_se
->run_list
);
7687 void __init
sched_init(void)
7690 unsigned long alloc_size
= 0, ptr
;
7692 #ifdef CONFIG_FAIR_GROUP_SCHED
7693 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7695 #ifdef CONFIG_RT_GROUP_SCHED
7696 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7698 #ifdef CONFIG_USER_SCHED
7702 * As sched_init() is called before page_alloc is setup,
7703 * we use alloc_bootmem().
7706 ptr
= (unsigned long)alloc_bootmem(alloc_size
);
7708 #ifdef CONFIG_FAIR_GROUP_SCHED
7709 init_task_group
.se
= (struct sched_entity
**)ptr
;
7710 ptr
+= nr_cpu_ids
* sizeof(void **);
7712 init_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
7713 ptr
+= nr_cpu_ids
* sizeof(void **);
7715 #ifdef CONFIG_USER_SCHED
7716 root_task_group
.se
= (struct sched_entity
**)ptr
;
7717 ptr
+= nr_cpu_ids
* sizeof(void **);
7719 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
7720 ptr
+= nr_cpu_ids
* sizeof(void **);
7723 #ifdef CONFIG_RT_GROUP_SCHED
7724 init_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
7725 ptr
+= nr_cpu_ids
* sizeof(void **);
7727 init_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
7728 ptr
+= nr_cpu_ids
* sizeof(void **);
7730 #ifdef CONFIG_USER_SCHED
7731 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
7732 ptr
+= nr_cpu_ids
* sizeof(void **);
7734 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
7735 ptr
+= nr_cpu_ids
* sizeof(void **);
7741 init_defrootdomain();
7744 init_rt_bandwidth(&def_rt_bandwidth
,
7745 global_rt_period(), global_rt_runtime());
7747 #ifdef CONFIG_RT_GROUP_SCHED
7748 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
7749 global_rt_period(), global_rt_runtime());
7750 #ifdef CONFIG_USER_SCHED
7751 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
7752 global_rt_period(), RUNTIME_INF
);
7756 #ifdef CONFIG_GROUP_SCHED
7757 list_add(&init_task_group
.list
, &task_groups
);
7758 INIT_LIST_HEAD(&init_task_group
.children
);
7760 #ifdef CONFIG_USER_SCHED
7761 INIT_LIST_HEAD(&root_task_group
.children
);
7762 init_task_group
.parent
= &root_task_group
;
7763 list_add(&init_task_group
.siblings
, &root_task_group
.children
);
7767 for_each_possible_cpu(i
) {
7771 spin_lock_init(&rq
->lock
);
7772 lockdep_set_class(&rq
->lock
, &rq
->rq_lock_key
);
7774 init_cfs_rq(&rq
->cfs
, rq
);
7775 init_rt_rq(&rq
->rt
, rq
);
7776 #ifdef CONFIG_FAIR_GROUP_SCHED
7777 init_task_group
.shares
= init_task_group_load
;
7778 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
7779 #ifdef CONFIG_CGROUP_SCHED
7781 * How much cpu bandwidth does init_task_group get?
7783 * In case of task-groups formed thr' the cgroup filesystem, it
7784 * gets 100% of the cpu resources in the system. This overall
7785 * system cpu resource is divided among the tasks of
7786 * init_task_group and its child task-groups in a fair manner,
7787 * based on each entity's (task or task-group's) weight
7788 * (se->load.weight).
7790 * In other words, if init_task_group has 10 tasks of weight
7791 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7792 * then A0's share of the cpu resource is:
7794 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7796 * We achieve this by letting init_task_group's tasks sit
7797 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
7799 init_tg_cfs_entry(&init_task_group
, &rq
->cfs
, NULL
, i
, 1, NULL
);
7800 #elif defined CONFIG_USER_SCHED
7801 root_task_group
.shares
= NICE_0_LOAD
;
7802 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, 0, NULL
);
7804 * In case of task-groups formed thr' the user id of tasks,
7805 * init_task_group represents tasks belonging to root user.
7806 * Hence it forms a sibling of all subsequent groups formed.
7807 * In this case, init_task_group gets only a fraction of overall
7808 * system cpu resource, based on the weight assigned to root
7809 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
7810 * by letting tasks of init_task_group sit in a separate cfs_rq
7811 * (init_cfs_rq) and having one entity represent this group of
7812 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
7814 init_tg_cfs_entry(&init_task_group
,
7815 &per_cpu(init_cfs_rq
, i
),
7816 &per_cpu(init_sched_entity
, i
), i
, 1,
7817 root_task_group
.se
[i
]);
7820 #endif /* CONFIG_FAIR_GROUP_SCHED */
7822 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
7823 #ifdef CONFIG_RT_GROUP_SCHED
7824 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
7825 #ifdef CONFIG_CGROUP_SCHED
7826 init_tg_rt_entry(&init_task_group
, &rq
->rt
, NULL
, i
, 1, NULL
);
7827 #elif defined CONFIG_USER_SCHED
7828 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, 0, NULL
);
7829 init_tg_rt_entry(&init_task_group
,
7830 &per_cpu(init_rt_rq
, i
),
7831 &per_cpu(init_sched_rt_entity
, i
), i
, 1,
7832 root_task_group
.rt_se
[i
]);
7836 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
7837 rq
->cpu_load
[j
] = 0;
7841 rq
->active_balance
= 0;
7842 rq
->next_balance
= jiffies
;
7845 rq
->migration_thread
= NULL
;
7846 INIT_LIST_HEAD(&rq
->migration_queue
);
7847 rq_attach_root(rq
, &def_root_domain
);
7850 atomic_set(&rq
->nr_iowait
, 0);
7853 set_load_weight(&init_task
);
7855 #ifdef CONFIG_PREEMPT_NOTIFIERS
7856 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
7860 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
, NULL
);
7863 #ifdef CONFIG_RT_MUTEXES
7864 plist_head_init(&init_task
.pi_waiters
, &init_task
.pi_lock
);
7868 * The boot idle thread does lazy MMU switching as well:
7870 atomic_inc(&init_mm
.mm_count
);
7871 enter_lazy_tlb(&init_mm
, current
);
7874 * Make us the idle thread. Technically, schedule() should not be
7875 * called from this thread, however somewhere below it might be,
7876 * but because we are the idle thread, we just pick up running again
7877 * when this runqueue becomes "idle".
7879 init_idle(current
, smp_processor_id());
7881 * During early bootup we pretend to be a normal task:
7883 current
->sched_class
= &fair_sched_class
;
7885 scheduler_running
= 1;
7888 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
7889 void __might_sleep(char *file
, int line
)
7892 static unsigned long prev_jiffy
; /* ratelimiting */
7894 if ((in_atomic() || irqs_disabled()) &&
7895 system_state
== SYSTEM_RUNNING
&& !oops_in_progress
) {
7896 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
7898 prev_jiffy
= jiffies
;
7899 printk(KERN_ERR
"BUG: sleeping function called from invalid"
7900 " context at %s:%d\n", file
, line
);
7901 printk("in_atomic():%d, irqs_disabled():%d\n",
7902 in_atomic(), irqs_disabled());
7903 debug_show_held_locks(current
);
7904 if (irqs_disabled())
7905 print_irqtrace_events(current
);
7910 EXPORT_SYMBOL(__might_sleep
);
7913 #ifdef CONFIG_MAGIC_SYSRQ
7914 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7918 update_rq_clock(rq
);
7919 on_rq
= p
->se
.on_rq
;
7921 deactivate_task(rq
, p
, 0);
7922 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
7924 activate_task(rq
, p
, 0);
7925 resched_task(rq
->curr
);
7929 void normalize_rt_tasks(void)
7931 struct task_struct
*g
, *p
;
7932 unsigned long flags
;
7935 read_lock_irqsave(&tasklist_lock
, flags
);
7936 do_each_thread(g
, p
) {
7938 * Only normalize user tasks:
7943 p
->se
.exec_start
= 0;
7944 #ifdef CONFIG_SCHEDSTATS
7945 p
->se
.wait_start
= 0;
7946 p
->se
.sleep_start
= 0;
7947 p
->se
.block_start
= 0;
7952 * Renice negative nice level userspace
7955 if (TASK_NICE(p
) < 0 && p
->mm
)
7956 set_user_nice(p
, 0);
7960 spin_lock(&p
->pi_lock
);
7961 rq
= __task_rq_lock(p
);
7963 normalize_task(rq
, p
);
7965 __task_rq_unlock(rq
);
7966 spin_unlock(&p
->pi_lock
);
7967 } while_each_thread(g
, p
);
7969 read_unlock_irqrestore(&tasklist_lock
, flags
);
7972 #endif /* CONFIG_MAGIC_SYSRQ */
7976 * These functions are only useful for the IA64 MCA handling.
7978 * They can only be called when the whole system has been
7979 * stopped - every CPU needs to be quiescent, and no scheduling
7980 * activity can take place. Using them for anything else would
7981 * be a serious bug, and as a result, they aren't even visible
7982 * under any other configuration.
7986 * curr_task - return the current task for a given cpu.
7987 * @cpu: the processor in question.
7989 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7991 struct task_struct
*curr_task(int cpu
)
7993 return cpu_curr(cpu
);
7997 * set_curr_task - set the current task for a given cpu.
7998 * @cpu: the processor in question.
7999 * @p: the task pointer to set.
8001 * Description: This function must only be used when non-maskable interrupts
8002 * are serviced on a separate stack. It allows the architecture to switch the
8003 * notion of the current task on a cpu in a non-blocking manner. This function
8004 * must be called with all CPU's synchronized, and interrupts disabled, the
8005 * and caller must save the original value of the current task (see
8006 * curr_task() above) and restore that value before reenabling interrupts and
8007 * re-starting the system.
8009 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8011 void set_curr_task(int cpu
, struct task_struct
*p
)
8018 #ifdef CONFIG_FAIR_GROUP_SCHED
8019 static void free_fair_sched_group(struct task_group
*tg
)
8023 for_each_possible_cpu(i
) {
8025 kfree(tg
->cfs_rq
[i
]);
8035 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8037 struct cfs_rq
*cfs_rq
;
8038 struct sched_entity
*se
, *parent_se
;
8042 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8045 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
8049 tg
->shares
= NICE_0_LOAD
;
8051 for_each_possible_cpu(i
) {
8054 cfs_rq
= kmalloc_node(sizeof(struct cfs_rq
),
8055 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
8059 se
= kmalloc_node(sizeof(struct sched_entity
),
8060 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
8064 parent_se
= parent
? parent
->se
[i
] : NULL
;
8065 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, 0, parent_se
);
8074 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
8076 list_add_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
,
8077 &cpu_rq(cpu
)->leaf_cfs_rq_list
);
8080 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8082 list_del_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
);
8085 static inline void free_fair_sched_group(struct task_group
*tg
)
8090 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8095 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
8099 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8104 #ifdef CONFIG_RT_GROUP_SCHED
8105 static void free_rt_sched_group(struct task_group
*tg
)
8109 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
8111 for_each_possible_cpu(i
) {
8113 kfree(tg
->rt_rq
[i
]);
8115 kfree(tg
->rt_se
[i
]);
8123 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8125 struct rt_rq
*rt_rq
;
8126 struct sched_rt_entity
*rt_se
, *parent_se
;
8130 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8133 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
8137 init_rt_bandwidth(&tg
->rt_bandwidth
,
8138 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
8140 for_each_possible_cpu(i
) {
8143 rt_rq
= kmalloc_node(sizeof(struct rt_rq
),
8144 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
8148 rt_se
= kmalloc_node(sizeof(struct sched_rt_entity
),
8149 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
8153 parent_se
= parent
? parent
->rt_se
[i
] : NULL
;
8154 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, 0, parent_se
);
8163 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
8165 list_add_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
,
8166 &cpu_rq(cpu
)->leaf_rt_rq_list
);
8169 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
8171 list_del_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
);
8174 static inline void free_rt_sched_group(struct task_group
*tg
)
8179 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8184 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
8188 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
8193 #ifdef CONFIG_GROUP_SCHED
8194 static void free_sched_group(struct task_group
*tg
)
8196 free_fair_sched_group(tg
);
8197 free_rt_sched_group(tg
);
8201 /* allocate runqueue etc for a new task group */
8202 struct task_group
*sched_create_group(struct task_group
*parent
)
8204 struct task_group
*tg
;
8205 unsigned long flags
;
8208 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
8210 return ERR_PTR(-ENOMEM
);
8212 if (!alloc_fair_sched_group(tg
, parent
))
8215 if (!alloc_rt_sched_group(tg
, parent
))
8218 spin_lock_irqsave(&task_group_lock
, flags
);
8219 for_each_possible_cpu(i
) {
8220 register_fair_sched_group(tg
, i
);
8221 register_rt_sched_group(tg
, i
);
8223 list_add_rcu(&tg
->list
, &task_groups
);
8225 WARN_ON(!parent
); /* root should already exist */
8227 tg
->parent
= parent
;
8228 list_add_rcu(&tg
->siblings
, &parent
->children
);
8229 INIT_LIST_HEAD(&tg
->children
);
8230 spin_unlock_irqrestore(&task_group_lock
, flags
);
8235 free_sched_group(tg
);
8236 return ERR_PTR(-ENOMEM
);
8239 /* rcu callback to free various structures associated with a task group */
8240 static void free_sched_group_rcu(struct rcu_head
*rhp
)
8242 /* now it should be safe to free those cfs_rqs */
8243 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
8246 /* Destroy runqueue etc associated with a task group */
8247 void sched_destroy_group(struct task_group
*tg
)
8249 unsigned long flags
;
8252 spin_lock_irqsave(&task_group_lock
, flags
);
8253 for_each_possible_cpu(i
) {
8254 unregister_fair_sched_group(tg
, i
);
8255 unregister_rt_sched_group(tg
, i
);
8257 list_del_rcu(&tg
->list
);
8258 list_del_rcu(&tg
->siblings
);
8259 spin_unlock_irqrestore(&task_group_lock
, flags
);
8261 /* wait for possible concurrent references to cfs_rqs complete */
8262 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
8265 /* change task's runqueue when it moves between groups.
8266 * The caller of this function should have put the task in its new group
8267 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8268 * reflect its new group.
8270 void sched_move_task(struct task_struct
*tsk
)
8273 unsigned long flags
;
8276 rq
= task_rq_lock(tsk
, &flags
);
8278 update_rq_clock(rq
);
8280 running
= task_current(rq
, tsk
);
8281 on_rq
= tsk
->se
.on_rq
;
8284 dequeue_task(rq
, tsk
, 0);
8285 if (unlikely(running
))
8286 tsk
->sched_class
->put_prev_task(rq
, tsk
);
8288 set_task_rq(tsk
, task_cpu(tsk
));
8290 #ifdef CONFIG_FAIR_GROUP_SCHED
8291 if (tsk
->sched_class
->moved_group
)
8292 tsk
->sched_class
->moved_group(tsk
);
8295 if (unlikely(running
))
8296 tsk
->sched_class
->set_curr_task(rq
);
8298 enqueue_task(rq
, tsk
, 0);
8300 task_rq_unlock(rq
, &flags
);
8304 #ifdef CONFIG_FAIR_GROUP_SCHED
8305 static void set_se_shares(struct sched_entity
*se
, unsigned long shares
)
8307 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
8308 struct rq
*rq
= cfs_rq
->rq
;
8311 spin_lock_irq(&rq
->lock
);
8315 dequeue_entity(cfs_rq
, se
, 0);
8317 se
->load
.weight
= shares
;
8318 se
->load
.inv_weight
= 0;
8321 enqueue_entity(cfs_rq
, se
, 0);
8323 spin_unlock_irq(&rq
->lock
);
8326 static DEFINE_MUTEX(shares_mutex
);
8328 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
8331 unsigned long flags
;
8334 * We can't change the weight of the root cgroup.
8339 if (shares
< MIN_SHARES
)
8340 shares
= MIN_SHARES
;
8341 else if (shares
> MAX_SHARES
)
8342 shares
= MAX_SHARES
;
8344 mutex_lock(&shares_mutex
);
8345 if (tg
->shares
== shares
)
8348 spin_lock_irqsave(&task_group_lock
, flags
);
8349 for_each_possible_cpu(i
)
8350 unregister_fair_sched_group(tg
, i
);
8351 list_del_rcu(&tg
->siblings
);
8352 spin_unlock_irqrestore(&task_group_lock
, flags
);
8354 /* wait for any ongoing reference to this group to finish */
8355 synchronize_sched();
8358 * Now we are free to modify the group's share on each cpu
8359 * w/o tripping rebalance_share or load_balance_fair.
8361 tg
->shares
= shares
;
8362 for_each_possible_cpu(i
)
8363 set_se_shares(tg
->se
[i
], shares
);
8366 * Enable load balance activity on this group, by inserting it back on
8367 * each cpu's rq->leaf_cfs_rq_list.
8369 spin_lock_irqsave(&task_group_lock
, flags
);
8370 for_each_possible_cpu(i
)
8371 register_fair_sched_group(tg
, i
);
8372 list_add_rcu(&tg
->siblings
, &tg
->parent
->children
);
8373 spin_unlock_irqrestore(&task_group_lock
, flags
);
8375 mutex_unlock(&shares_mutex
);
8379 unsigned long sched_group_shares(struct task_group
*tg
)
8385 #ifdef CONFIG_RT_GROUP_SCHED
8387 * Ensure that the real time constraints are schedulable.
8389 static DEFINE_MUTEX(rt_constraints_mutex
);
8391 static unsigned long to_ratio(u64 period
, u64 runtime
)
8393 if (runtime
== RUNTIME_INF
)
8396 return div64_u64(runtime
<< 16, period
);
8399 #ifdef CONFIG_CGROUP_SCHED
8400 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
8402 struct task_group
*tgi
, *parent
= tg
->parent
;
8403 unsigned long total
= 0;
8406 if (global_rt_period() < period
)
8409 return to_ratio(period
, runtime
) <
8410 to_ratio(global_rt_period(), global_rt_runtime());
8413 if (ktime_to_ns(parent
->rt_bandwidth
.rt_period
) < period
)
8417 list_for_each_entry_rcu(tgi
, &parent
->children
, siblings
) {
8421 total
+= to_ratio(ktime_to_ns(tgi
->rt_bandwidth
.rt_period
),
8422 tgi
->rt_bandwidth
.rt_runtime
);
8426 return total
+ to_ratio(period
, runtime
) <
8427 to_ratio(ktime_to_ns(parent
->rt_bandwidth
.rt_period
),
8428 parent
->rt_bandwidth
.rt_runtime
);
8430 #elif defined CONFIG_USER_SCHED
8431 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
8433 struct task_group
*tgi
;
8434 unsigned long total
= 0;
8435 unsigned long global_ratio
=
8436 to_ratio(global_rt_period(), global_rt_runtime());
8439 list_for_each_entry_rcu(tgi
, &task_groups
, list
) {
8443 total
+= to_ratio(ktime_to_ns(tgi
->rt_bandwidth
.rt_period
),
8444 tgi
->rt_bandwidth
.rt_runtime
);
8448 return total
+ to_ratio(period
, runtime
) < global_ratio
;
8452 /* Must be called with tasklist_lock held */
8453 static inline int tg_has_rt_tasks(struct task_group
*tg
)
8455 struct task_struct
*g
, *p
;
8456 do_each_thread(g
, p
) {
8457 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
8459 } while_each_thread(g
, p
);
8463 static int tg_set_bandwidth(struct task_group
*tg
,
8464 u64 rt_period
, u64 rt_runtime
)
8468 mutex_lock(&rt_constraints_mutex
);
8469 read_lock(&tasklist_lock
);
8470 if (rt_runtime
== 0 && tg_has_rt_tasks(tg
)) {
8474 if (!__rt_schedulable(tg
, rt_period
, rt_runtime
)) {
8479 spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8480 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
8481 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
8483 for_each_possible_cpu(i
) {
8484 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
8486 spin_lock(&rt_rq
->rt_runtime_lock
);
8487 rt_rq
->rt_runtime
= rt_runtime
;
8488 spin_unlock(&rt_rq
->rt_runtime_lock
);
8490 spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8492 read_unlock(&tasklist_lock
);
8493 mutex_unlock(&rt_constraints_mutex
);
8498 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
8500 u64 rt_runtime
, rt_period
;
8502 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8503 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
8504 if (rt_runtime_us
< 0)
8505 rt_runtime
= RUNTIME_INF
;
8507 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8510 long sched_group_rt_runtime(struct task_group
*tg
)
8514 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
8517 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
8518 do_div(rt_runtime_us
, NSEC_PER_USEC
);
8519 return rt_runtime_us
;
8522 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
8524 u64 rt_runtime
, rt_period
;
8526 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
8527 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8529 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8532 long sched_group_rt_period(struct task_group
*tg
)
8536 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8537 do_div(rt_period_us
, NSEC_PER_USEC
);
8538 return rt_period_us
;
8541 static int sched_rt_global_constraints(void)
8545 mutex_lock(&rt_constraints_mutex
);
8546 if (!__rt_schedulable(NULL
, 1, 0))
8548 mutex_unlock(&rt_constraints_mutex
);
8553 static int sched_rt_global_constraints(void)
8555 unsigned long flags
;
8558 spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8559 for_each_possible_cpu(i
) {
8560 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
8562 spin_lock(&rt_rq
->rt_runtime_lock
);
8563 rt_rq
->rt_runtime
= global_rt_runtime();
8564 spin_unlock(&rt_rq
->rt_runtime_lock
);
8566 spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8572 int sched_rt_handler(struct ctl_table
*table
, int write
,
8573 struct file
*filp
, void __user
*buffer
, size_t *lenp
,
8577 int old_period
, old_runtime
;
8578 static DEFINE_MUTEX(mutex
);
8581 old_period
= sysctl_sched_rt_period
;
8582 old_runtime
= sysctl_sched_rt_runtime
;
8584 ret
= proc_dointvec(table
, write
, filp
, buffer
, lenp
, ppos
);
8586 if (!ret
&& write
) {
8587 ret
= sched_rt_global_constraints();
8589 sysctl_sched_rt_period
= old_period
;
8590 sysctl_sched_rt_runtime
= old_runtime
;
8592 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
8593 def_rt_bandwidth
.rt_period
=
8594 ns_to_ktime(global_rt_period());
8597 mutex_unlock(&mutex
);
8602 #ifdef CONFIG_CGROUP_SCHED
8604 /* return corresponding task_group object of a cgroup */
8605 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
8607 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
8608 struct task_group
, css
);
8611 static struct cgroup_subsys_state
*
8612 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8614 struct task_group
*tg
, *parent
;
8616 if (!cgrp
->parent
) {
8617 /* This is early initialization for the top cgroup */
8618 init_task_group
.css
.cgroup
= cgrp
;
8619 return &init_task_group
.css
;
8622 parent
= cgroup_tg(cgrp
->parent
);
8623 tg
= sched_create_group(parent
);
8625 return ERR_PTR(-ENOMEM
);
8627 /* Bind the cgroup to task_group object we just created */
8628 tg
->css
.cgroup
= cgrp
;
8634 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8636 struct task_group
*tg
= cgroup_tg(cgrp
);
8638 sched_destroy_group(tg
);
8642 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8643 struct task_struct
*tsk
)
8645 #ifdef CONFIG_RT_GROUP_SCHED
8646 /* Don't accept realtime tasks when there is no way for them to run */
8647 if (rt_task(tsk
) && cgroup_tg(cgrp
)->rt_bandwidth
.rt_runtime
== 0)
8650 /* We don't support RT-tasks being in separate groups */
8651 if (tsk
->sched_class
!= &fair_sched_class
)
8659 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8660 struct cgroup
*old_cont
, struct task_struct
*tsk
)
8662 sched_move_task(tsk
);
8665 #ifdef CONFIG_FAIR_GROUP_SCHED
8666 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
8669 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
8672 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
8674 struct task_group
*tg
= cgroup_tg(cgrp
);
8676 return (u64
) tg
->shares
;
8680 #ifdef CONFIG_RT_GROUP_SCHED
8681 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
8684 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
8687 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
8689 return sched_group_rt_runtime(cgroup_tg(cgrp
));
8692 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
8695 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
8698 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
8700 return sched_group_rt_period(cgroup_tg(cgrp
));
8704 static struct cftype cpu_files
[] = {
8705 #ifdef CONFIG_FAIR_GROUP_SCHED
8708 .read_u64
= cpu_shares_read_u64
,
8709 .write_u64
= cpu_shares_write_u64
,
8712 #ifdef CONFIG_RT_GROUP_SCHED
8714 .name
= "rt_runtime_us",
8715 .read_s64
= cpu_rt_runtime_read
,
8716 .write_s64
= cpu_rt_runtime_write
,
8719 .name
= "rt_period_us",
8720 .read_u64
= cpu_rt_period_read_uint
,
8721 .write_u64
= cpu_rt_period_write_uint
,
8726 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
8728 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
8731 struct cgroup_subsys cpu_cgroup_subsys
= {
8733 .create
= cpu_cgroup_create
,
8734 .destroy
= cpu_cgroup_destroy
,
8735 .can_attach
= cpu_cgroup_can_attach
,
8736 .attach
= cpu_cgroup_attach
,
8737 .populate
= cpu_cgroup_populate
,
8738 .subsys_id
= cpu_cgroup_subsys_id
,
8742 #endif /* CONFIG_CGROUP_SCHED */
8744 #ifdef CONFIG_CGROUP_CPUACCT
8747 * CPU accounting code for task groups.
8749 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
8750 * (balbir@in.ibm.com).
8753 /* track cpu usage of a group of tasks */
8755 struct cgroup_subsys_state css
;
8756 /* cpuusage holds pointer to a u64-type object on every cpu */
8760 struct cgroup_subsys cpuacct_subsys
;
8762 /* return cpu accounting group corresponding to this container */
8763 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
8765 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
8766 struct cpuacct
, css
);
8769 /* return cpu accounting group to which this task belongs */
8770 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
8772 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
8773 struct cpuacct
, css
);
8776 /* create a new cpu accounting group */
8777 static struct cgroup_subsys_state
*cpuacct_create(
8778 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8780 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
8783 return ERR_PTR(-ENOMEM
);
8785 ca
->cpuusage
= alloc_percpu(u64
);
8786 if (!ca
->cpuusage
) {
8788 return ERR_PTR(-ENOMEM
);
8794 /* destroy an existing cpu accounting group */
8796 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8798 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8800 free_percpu(ca
->cpuusage
);
8804 /* return total cpu usage (in nanoseconds) of a group */
8805 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
8807 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8808 u64 totalcpuusage
= 0;
8811 for_each_possible_cpu(i
) {
8812 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, i
);
8815 * Take rq->lock to make 64-bit addition safe on 32-bit
8818 spin_lock_irq(&cpu_rq(i
)->lock
);
8819 totalcpuusage
+= *cpuusage
;
8820 spin_unlock_irq(&cpu_rq(i
)->lock
);
8823 return totalcpuusage
;
8826 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
8829 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8838 for_each_possible_cpu(i
) {
8839 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, i
);
8841 spin_lock_irq(&cpu_rq(i
)->lock
);
8843 spin_unlock_irq(&cpu_rq(i
)->lock
);
8849 static struct cftype files
[] = {
8852 .read_u64
= cpuusage_read
,
8853 .write_u64
= cpuusage_write
,
8857 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8859 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
8863 * charge this task's execution time to its accounting group.
8865 * called with rq->lock held.
8867 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
8871 if (!cpuacct_subsys
.active
)
8876 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, task_cpu(tsk
));
8878 *cpuusage
+= cputime
;
8882 struct cgroup_subsys cpuacct_subsys
= {
8884 .create
= cpuacct_create
,
8885 .destroy
= cpuacct_destroy
,
8886 .populate
= cpuacct_populate
,
8887 .subsys_id
= cpuacct_subsys_id
,
8889 #endif /* CONFIG_CGROUP_CPUACCT */